TRADE PREAMBLES AND SPECIFICATIONS

GENERALLY

A. MATERIALS GENERALLY

All materials used in the works shall be new and of the qualities and kinds specified

herein and equal to approved samples. Deliveries shall be made sufficiently in

advance to enable samples to be taken and tested if required. No materials shall be

used until approved and all materials which are not approved or which are damaged,

contaminated or have deteriorated in any way do not comply with the requirements

of this Specification shall be rejected and shall be immediately removed from the Site

at the Contractor’s expense.

B. KENYA STANDARDS AND BRITISH STANDARDS

All materials used in the works for which a Kenya Standard Specification is published

shall conform to latest Edition thereof in every way. Materials for which no Kenya

Standard exists but which are covered by a British Standard shall conform to the latest

Edition of that Standard.

Where materials are covered by both a Kenya Standard and British Standard the Kenya

Standard will override the British Standard where inconsistencies occur.

The Architect reserves the right to demand that the Contractor obtain at his own expense a

certificate in respect of any material to state that it is in accordance with a Kenya or

British Standard Specification.

C. MATERIALS FOR WHICH THERE IS NO STANDARD

All materials used in the work for which no Kenya or British Standard Specification has

been published shall be the best of their respective kinds and of a standard to the

satisfaction of the Architect. The quality of such materials shall be generally of a

standard equal to those for which there is a Kenya or British Standard Specification.

D. ALTERNATIVES TO PROPRIETARY BRANDS

Where materials are specified by their proprietary names or where fittings are specified

by catalogue numbers, or descriptions, the Contractor may offer materials or fittings of

alternative manufacture which are of equal quality. Such alternatives must be approved

before being used in the works and the Contractor shall allow for this, but prior to

tendering he may submit to the Architect for approval, the names of any suppliers or

manufacturers whose products he intends to use, together with catalogue numbers, and

descriptions and/or samples but the decision of the Architect will be final.

E. MEASURING AND TESTING EQUIPMENT

The Contractor shall provide the following equipment for carrying out measuring and

control tests on the Site and maintain in full working order: -

1. Straight edges 2 metres and 4 metres long for testing the accuracy of the finished

concrete.

2. A glass graduated cylinder for use in the silt test for organic impurities in the sand.

3. Slump test apparatus.

4. 150mm Steel cube moulds with base plates and tamping rods to B.S. 1881. Two 30

metre steel tapes.

5. One dumpy or quickest level and staff.

A. PRICING NOTES GENERALLY

a. The rates set down by the Contractor against each item shall unless

otherwise expressly provided to the contrary, or unless there is a separate

item for extra labour, cutting or waste, be held to include for waste on

materials, carriage, and cartage, carrying in and return of empties, hoisting,

setting, fitting and fixing in position, marking all other labours and

everything else necessary for the proper completion of each item and or

establishment charges and profit.

b. Throughout the Bills of Quantities generally no mention is made of heights for

hoisting and all prices must include for hoisting and fixing at any level

within the limit shown on the drawings or include in the general description

unless a specific level stated.

c. The Contractor shall be deemed to have made allowance in his rates

generally to cover items of Preliminaries, expenses in connection with

Prime Cost Sums or other items if these have not been priced against the

respective items.

EXCAVATION

B. INSPECTION OF SITE

The Contractor is deemed to have visited the site and to have ascertained the nature

of the soil and sub-soils to be excavated. No claim will be allowed on account of

these being of a different nature from that for which he has allowed in his prices.

C. PROCEDURE

The excavations and fillings shall be carried out in such a manner and order as the

Architect may direct.

D. EXISTING TREES AND SHRUBS

Cut down and remove shrubs and trees as directed. No shrubs, trees, plants, etc. shall

be removed except as directed by the Architect and the contractor shall be held

responsible for any damage caused by the building operations to those shrubs, trees,

etc., not so directed to be removed.

E. SITE CLEARANCE

All grass, vegetable matter etc., must be removed or burned on site at the commencement of

the Contract over areas as directed by the Architect.

A. WHITE ANT – INSPECTION TREATMENT

The Contractor must destroy any white ants’ nest found within the perimeter of the

buildings and within a distance of 20 metres from the buildings externally and take out

and destroy Queen Ants, impregnate holes and tunnels with approved insecticide and

back-fill with hard material well rammed and consolidated.

B. EXCAVATION

The excavations are to be executed to the widths shown on the Drawings, and to the

depths below existing ground level as directed by the Architect in order to obtain

satisfactory foundation. If the Contractor excavates to any widths or depths greater than

those shown on the drawings or as instructed by the Architect he shall at his own

expense fill in such widths or depths of excavation beyond that instructed or shown with

concrete as specified by the Architect.

I. Level and ram bottoms of all excavations to receive concrete form

stepping if necessary or directed to allow for sloping ground and well water

excavations before pouring concrete.

II. The Contractor shall report to the Architect when secure bottoms to the

excavations have been obtained. Any concrete or other work executed before the

excavations have been inspected and approved shall, if so directed, be removed and

new work substituted after the excavations have been approved all at the

contractor’s expense.

C. ROCK

i) Rock is defined as any material met with in the excavation which is of

such size or position that it can only be removed by means of wedges,

compressed air plant, other special plant or explosives and the

Architect’s opinion shall be final. Excavation in any material such

as soft coral, hard murram, stiff clay or similar materials which in the

opinion of the Architect can reasonably be removed by pick,

traxcavator or similar means will be deemed to be included in the

prices for normal excavation.

ii) All materials classified as rock may, if approved by the Architects be

used as hardcore filling and the measured quantities of imported filling

will be adjusted accordingly. All rock so used must be broken to the

required size as hereafter described before being so used.

D. BLASTING

Blasting will only be allowed with the written permission of the Architect. All blasting

operations shall be carried out at the sole risk and cost of the contractor and in

accordance with any Government regulations in force for the time being, and any special

regulations laid down by the Architect governing the use and storage of explosives.

E. BURROW PITS

Burrow pits will only be allowed to be opened up on site at the written permission of the

Architect.

A. HARDCORE FILLING (OTHER THAN CORAL OBTAINED FROM

EXCAVATIONS)

Hardcore for filling under floors, etc., shall be good hard stone of coral, ballast or quarry

waste (not soft coral) to the approval of the Architect broken to pass not greater than

150mm ring or to be 75% of the finished thickness of the layers being compacted

whichever is the lesser and graded to contain sufficient smaller pieces to fill all voids so

that it can be thoroughly compacted. The filling is to be in layers each of a consolidated

thickness not exceeding 225mm and well watered and compacted by hand or mechanical

tampers. The top surface of the hardcore shall be levelled or graded to falls as required

and blinded with a 75m layer of similar material finely crushed and well rolled and

watered immediately before concrete is laid.

B. FILLING OBTAINED FROM THE EXCAVATIONS

Filling obtained from surplus excavated materials is to be free from all weeds, roots,

vegetable or other unsuitable materials and is to be filled in layers each of not more than

225mm finished thickness. Each layer to be well watered and consolidated before the

subsequent layer is filled in.

C. MATERIALS FOUND IN THE EXCAVATIONS

No sand, aggregate or other material found in the excavations is to be used in the works

without written permission of the Architect.

D. POLYTHENE MEMBRANE

(i) Where the joints occur there is to be a minimum of 300mm welted lap or

joint made with approved tapes.

(ii) The Contractor shall ensure that the membrane will not be pierced during

the laying and concreting of sub-floors

E. INSECTICIDE TREATMENT

(i) Insecticide treatment shall be “Aldrex” 48 or “Dieldrex” 18 (to be obtained

from Kenya Shell Limited. P.O. Box 43561, Nairobi.) applied in accordance

with the Manufacturer’s printed instructions or other equal and approved

treatment.

(ii) After the hardcore filling has been prepared the whole surface including

the top surface of foundation walling shall be similarly treated before

concrete slabs are poured. The treatment shall extend 1.5 metres beyond the

external wall faces of the building.

F. PRICING NOTES

Prices shall include for excavating in any material encountered unless specifically measured.

Excavation and disposal of soil are measured net before excavation, filling is measured net

after consolidation.

Prices shall include for handling, etc., of extra bulk after excavating, or before consolidating,

any extra excavation required for formwork or planking and strutting, circular work,

grubbing up any old drains, roots, etc., that may be encountered and for well watering

bottoms before laying concrete unless specifically measured.

Prices for returning, filling and ramming or carting away are to include for

removing the excavated materials to temporary heaps or dumps, etc., as required

or made necessary by the progress of the works, site conditions, etc., and for any

re-excavating, re-handling and transporting from such heaps or dumps. All

excavated material has been either returned, filled in and rammed or carted away

and therefore the rates for these items must include for all costs involved in

getting this material to its final position.

The thickness of all soil, hardcore etc., beds given herein is thickness after

consolidation.

The term formation level used in descriptions of work means the level after general excavation

to reduce levels of Site or where there is no such bulk excavation the level after removal of

surface soil.

CONCRETE

A. DESIGNATION OF CONCRETE MIXES

The various mixes of concrete are designated in the subsequent measured items

by the following criteria:-

Nominal mixes: By the weight proportions of whole bags of ordinary Portland

cement to fine and coarse aggregate and by the maximum size of coarse

aggregate. The Contractor shall regularly submit details giving specific

gravities and moisture content of aggregates.

B. TAMPING

The term “tamping” as used herein in conjunction with the phrase treating surfaces of

unset concrete” shall mean the final compaction and surface finish to be applied to unset

concrete beds, or the like, with steel shod beam tamper, either manually or mechanically

operated unless otherwise stated. The resulting surface finish shall have a slightly ribbed

appearance.

C. KEYING

The term“Keying” as used herein in conjunction with the phrase “treating surfaces of

unset concrete” shall mean the preparation of beds, or the like, to receive insitu pavings

by raking with a standard horticultural rake whilst the concrete is still green and when the

concrete is set and cured, protecting the raked surfaces with a layer of clean sand and

removing the sand immediately before the insitu paving is laid.

D. PRECAST CONCRETE UNITS

Unless otherwise described in the measured items, precast concrete units are deemed to

be basically rectangular in cross section and rough on exposed faces. Reinforcement bars

shall have hooked ends. Bedding and pointing mortar shall be either cement or

cement lime mortar, as appropriate, and units shall be deemed to be fixed by hoisting,

bedding and building in unless otherwise described.

Nominally non-reinforced units may contain any reinforcement the Contractor may wish

to Introduce for handling purposes.

GENERALLY

A. STANDARDS

The whole of the concrete work and testing thereof shall comply with British Standard

Code of Practice No. 114 and with the subsequent clauses of this Document and shall

be carried out in strict accordance with the working drawings and instructions of the

Architect and the Structural Engineer.

A competent person shall be employed whose first duty will be to supervise all stages in

the preparation and placing of the concrete. All cubes should be made and site tests

carried out under his direct supervision. This person shall also be responsible for keeping

an accurate record of the dates on which concrete is poured.

B. BAR BENDING SCHEDULES

The Structural Engineer will prepare and provide all necessary bar bending schedules

and explanatory details.

The Contractor shall check these bending schedules against the corresponding drawings

before any cutting or bending. Any discrepancies shall be reported to the Engineer.

The Contractor shall be responsible for any delays or additional work caused by his

failure to check the schedules.

MATERIALS

C. SAMPLES

Samples of all materials are to be submitted for approval of the Architect at least one

week before it is desired to commence deliveries. All condemned materials are to be

removed from the site within 24 hours.

D. CEMENT

Cement shall comply with Kenya Standard as follows:-

Portland cement - K.S. 02-21

Rapid hardening cement - K.S. 02-21

Sulphate resisting Portland cement shall comply with - B.S. 4027

Rapid hardening cement may be used in lieu of ordinary Portland cement only with the

prior approval of the Architect or Engineer, provided that all conditions applying to its

use are strictly observed. Any additional expense in connection with the use of such

cement shall be borne by the Contractor.

The use of high alumina cement will not be permitted. All cement shall be

delivered to the site in sealed bags bearing the mark of the manufacturer. Rebagged

cement, cement in plain bags and cement in torn bags will not be allowed on the site.

Each consignment of cement shall be accompanied by the manufacturer’s certificate

showing that a representative sample of the consignment has been tested and compiles

with the appropriate specification.

From time to time as requested by the Architect, copies of the cement manufacturer’s test

certificate shall be delivered to the Architect or his representative on the site promptly,

but such documents shall not preclude the Architect from rejecting any cement which

does not in every way comply with the specification.

Any cement, which has failed to pass the tests or has been damaged by water or

contaminated in any way on site, shall immediately be removed from the site.

A. AGGREGATES

Aggregates shall comply with British Standards as follows:-

Fine - B.S. 882 table 2 Zone

1 to 3 only.

Coarse - B.S. 882 graded

“All in” ballast - B.S. 882 graded

Granite - B.S. 1201 graded

B. AGGREGATE

Each type aggregate shall be obtained from one approved source, capable of

maintaining adequate supplies of consistently graded material throughout the

contract. Aggregates for exposed concrete shall be free from all impurities

likely to cause discolouration and shall be of consistent colour throughout the

work.

Fine aggregates and sand shall be clean, sharp, coarse, hard material and equal at

all times to the samples which shall be deposited with and approved by the

engineer. The caustic soda test for organic impurities shall show a colour not

deeper than that of the standard solution. The setting test for natural sand shall

be made after being allowed to settle for three hours the layer of silt deposit on

the coarse material shall not exceed 10%.

The contractor shall supply necessary equipment for the testing of fine

aggregate and sand for the use of the Engineer.

Coarse aggregates shall be hard , clean gravel or broken stone from approved

quarries and shall be free from earth, decomposed stone, and extraneous matter.

They shall conform to B.S. 882 and shall be “Graded Aggregate” 20mm to

5mm. Thin, elongated, friable, flaky or laminated pieces, mica or shale shall

only be present in such small quantities as not to affect adversely the strength

and durability of the concrete. The amount of fine particles occurring in a free

state or as loose adherent shall not exceed 1% when determined by the laboratory

sedimentation test. After twenty-four hours in water, a previously fried sample

shall not gain more than 10% in weight.

Each grade of aggregate shall be stored in the works in separate heaps so that

there shall be no possibility of any inter-mixing. Any materials which have

become inter-mixed shall be removed from the site forthwith by the Contractor.

If, in the opinion of the Engineer, the aggregate is dirty or adulterated in any

manner, it shall be wasted and or/ screened by the Contractor.

Graded samples of all types of aggregate each weighing 10Kg. Shall after

approval, be kept on site behind glass for visual checking of subsequent

deliveries for grading, shape, and where applicable, colour.

A. REINFORCEMENT

Reinforcement shall comply with the following standards: -

(a) Mild steel rod reinforcement shall be – K.S. 02-22

(b) High tensile steel reinforcement shall either be cold worked deformed steel

bars of circular octagonal section complying with B.S. 4461 or hot rolled

deformed high tensile bars having a guarantee minimum yield stress of

4200 kg/sq. cm (60,000 p.s.i) and other physical qualities in accordance

with B.S. 4449.

(c) Welded steel fabric reinforcement shall comply with B.S. 4483.

All reinforcement shall be in the “diameter” and metric range and the substitution of “square

twisted” or imperial range shall be allowed but only at no extra cost to the Employer.

The Contractor will be required to submit at his own expense certified test data of the

following characteristics; ultimate tensile stress, yield point stress, elongation, cold

bend test. Should such certificates not be submitted by the manufacturer, the

Contractor shall have the requisite tests made at his own expense at an independent

testing laboratory.

B. EXPANSION JOINTS – FILLERS AND SEALERS

(i) Filler shall be Flexcell” impregnated fibreboard joint filler.

Top edges of filler to be covered with plastic tapes as a bond-breaking

barrier prior to filling with sealer.

(ii) Sealers to be

a) “Pli-astic” grade 99 applied hot with a machine pourer as recommended by

the manufacturers. Prior to application surfaces to be treated with a brush coat of

Expandite No. 3 Primer. or

b) “Plastic joint” hand applied bitumen putty sealant prior to application

surfaces to be primed as last. or

c) “High duty” sealer cold applied to sealant. Porous

surfaces to be primed with Expandite No. 20 primer.

iii) The appropriate sealers are specified in the measured work hereafter and must all be

applied and used strictly in accordance with the manufacturers’ printed instructions.

A. WALL TIES

Wall ties shall be provided between all columns and walling and shall be of

galvanised mild steel strip 25mm wide x 450mm long.

B. WATER

Water shall be from the mains and kept free of any impurities and acid or alkaline

substances in suspension or in solution, and shall be stored in proper storage tanks

to the approval of the Architect.

C. STORAGE OF MATERIALS

Cement shall be kept dry and used in rotation of deliveries. If delivered in bags

these shall be stored off the ground in a well-ventilated and weatherproof shed used

exclusively for this purpose.

The shed is to be sufficiently large to contain a working stock and provided with

partitions or such other means as may be necessary to ensure the effectual separation

of the various consignments and type of cement. Stacking of cement in bags over a

height of ten bags will not be permitted. Cement may be delivered in bulk

containers provided additional suitable arrangements are made for bulk storage on

the approval of the Architect.

Aggregate shall be stored at mixer positions on drained concrete paved areas, with stout

dividing walls between different sizes and types of aggregates.

Reinforcement shall be stored by type, size and length either off the ground or on

clean surfaced areas, and shall be kept free from rust.

D. PROPORTIONS OF CONCRETE MIX

The quantity of cement shall be measured by weight and each batch of concrete is to

use one or more whole bags. The quantity of fine aggregate and coarse aggregate

shall be measured separately by weight-batching plant. Volume mixing will not be

permitted.

For grading test the Contractor shall supply and deliver at his own cost to the

Approved Testing Authority, samples of the aggregates which the Contractor

proposes to use, consisting of not less than 50 Kilograms weight in fine aggregate.

It is the Contractor’s responsibility to ensure that the subsequent deliveries of

aggregate conform to the grading analysis of the approved samples.

The proportions of materials to be used for the preliminary cube tests and subsequent

batching, shall be ascertained by calculation from the results of the aggregate

grading tests carried out by the Approved Testing Authority.

Preliminary concrete cubes shall be made by the Contractor on site as required by the

Engineer and tested by the Approved Testing Authority. As a result of these tests

definite weights of each material for batching shall be ascertained and agreed with

the Engineer. Thereafter these proportions shall be adhered to throughout the works

and may be varied only by the instructions given by the Engineer.

The weights of damp aggregate must be adjusted to take into account the weight of

water in the aggregates, and this in turn will affect the amount of water to be added

into the mix.

Throughout the carrying out of the Contract, “works Cube Tests” are to be made from

concrete drawn from newly laid concrete or concrete about to be placed in position,

such cubes being made when directed by the Engineer and in his presence. Such cubes

shall be made in 150mm cube steel or cast iron moulds and shall be marked and cured

strictly in accordance with the Appendices of the Code of Practice, and shall be

forwarded carriage paid in time for testing at the required age to the testing laboratory

approved by the Engineer.

Three cubes shall be made on each occasion, concrete for each cube being from a

different batch. Two cubes shall be forwarded in time for testing in twenty-eight days.

Each cube shall be marked with the date of casting and a distinctive reference number in

accordance with a system agreed by the Engineer.

A record shall be kept of the position from which the concrete for each set of cubes was

drawn, or to which it was about to be placed.

At least three sets of three cubes shall be cast during each week concrete is being cast

including sets of cubes for each quality of concrete used during the period, or at

frequency agreed by the Engineer.

Concrete is required to have the properties and give the strength Newtons per square

millimetres as follows:-

Class Mix Max. – size Max. water Min. crushing

of coarse cement ratio strength of

aggregate by weight works Test

Cubes in N/mm

7 days 28 days

30 1:1:2 20mm 0.50 21 81.50

25 1:1 ½:3 20mm 0.55 17.5 26.25

20 1:2:4 20mm 0.60 14 21

20 1:2:4 15mm 0.60 14 21

15 1:3:6 25mm 0.60 9 13.5

10 1:4:8 40mm 0.60 - -

The above properties and crushing strength are to be considered as the minimum

standard that will be accepted in the finished works.

If the strengths required in the table are not attained and maintained throughout the

carrying out the contract, the contractor will be required to increase the proportion

of cement or substitute aggregates at his own cost so as to give concrete which does

comply with the requirements of this clause.

The Contractor may be required to remove and replace at his own cost any concrete

which fails to attain the required strength as ascertained by the Works Cube Tests.

A. TESTING OF MATERIALS GENERALLY

The Contractor shall include in his tender prices for the execution of his part of operations

specified for testing herein and for supply of the requisite equipment.

After initial testing and approval of materials, it is the Contractor’s responsibility to

ensure and to demonstrate by the submission of further similar samples when so required

that subsequent deliveries conform to the quality, grading and (where applicable), colour

of the approved samples.

B TESTING OF CEMENT

Before work commences and when subsequently directed, the Contractor shall take 6 kg

samples, in accordance with B.S. 12 procedure, of cement and deliver these in tins

approved by the Engineer to an approved testing Laboratory for testing.

Each consignment of cement to the site, which shall be accompanied by the

manufacturer’s advice note and forwarded without delay to the Engineer, shall be

Delivered to the site at least 7 days before it is intended to be used in the works so that

the required tests may be carried out without retarding the progress of the works.

C. TESTING OF AGGREGATES

Before work commences and when subsequently instructed, the Contractor

Shall take the site samples, by methods given in B.S. 812, and deliver to the

approved Testing Authority for testing.

Such samples shall be submitted for approval at least 7 days before they are

intended to be used in the works.

D. TESTING OF REINFORCEMENT

Should the Engineer require reinforcement to be tested, it shall be tested at the

Contractor’s expenses and representative test pieces of such reinforcement to be

used in the works are to be sent to an approved laboratory for testing.

E. TESTING OF CONCRETE IN THE FIELD

Trial mixture

Prior to the commencement of the actual concrete work, the Contractor shall make, or

have made, Preliminary Test Cubes in accordance with B.S. 1881, using the aggregate

from which samples were taken for grading analyses. Six cubes are to be made on each

occasion, 3 for testing at 7 days and 3 for testing at 28 days. The cube strengths obtained

in the preliminary tests should show crushing strengths of at least 11/3 times the specified

works cube test strengths.

The Preliminary Test Cubes will be submitted to an approved Testing Authority for

crushing, and from the results of these tests, definite weights of each material for

batching will be ascertained, and agreed with the Engineer.

Thereafter these proportions shall be adhered to throughout the works, and may be varied

only by instructions form the Engineer.

If any of the concrete materials are to be varied or obtained from a different source, a

further set of Preliminary Cube Tests, using the proposed new materials, will be required.

Workability

The total water content in the mixture determines its consistency and once a consistency

of a trial mix has been approved it must remain constant throughout the Contract.

In order to help the concrete maintain the desired consistency the slump of an approved

trial mix shall be measured thereafter all mixes must give the slump as the approved

trial mix. The slump shall be determined by the test as described in B.S. 1881 Part 2. In

general, the approved slump shall be in the order of 75mm for hand compacted concrete

and 35mm for vibrated concrete. The slump test shall be made on concrete actually

being placed in the works at the commencement of each period of concrete placing and at

such other times as instructed.

Test specimens

The moulds for tests cubes shall be of metal and true to shape to give a 150mm cube and

shall be well oiled before filling. The mould shall be filled with concrete taken from that

actually placed in the works, the concrete being selected by the Engineer from a point as

near as possible to the position of placing. The filling of the moulds shall be done

immediately after the selection of the sample concrete and in such a way that the concrete

in the moulds be truly representative that in the works.

The concrete shall be placed in the moulds in three layers of equal thickness, each layer

being rammed with 25 strokes of a steel bar 40mm diameter, (or equivalent) weighing

2kg. If the concrete in the works is to be consolidated by mechanical vibration, the test

cube moulds shall be likewise vibrated after filling. Each cube shall be inscribed with

the date of manufacture and identification mark,.

A record shall be kept for each batch of cubes showing the position in the works, which

the concrete represents, the date of manufacture, the mixture and slump of the concrete,

particulars of the cement and aggregate used, a statement of whether or not the cubes

were vibrated and other information relating to the subsequent history of the cubes.

The moulds containing the test cubes shall be stored for 24 hours on the site in a damp

place free from vibration. At the end of this period the cubes shall be taken from the

moulds and stored in damp sand for 20 days if they are to be tested at 28 days, or for 4

days if they are to be tested at 7 days.

The Contractor shall be instructed about the dispatch of the cubes to an approved

laboratory and will pay all costs relating to the tests. A set of three cubes will be required

for not more than every 60 cubic metres of concrete placed in the works.

Quality of specimens

The test specimens shall have the compressive strength specified for each quality of

concrete at the appropriate age as given herein.

If the required strength is not obtained at 28 days, the Contractor will be required to cut

out and reconstruct all work represented by the test specimens at his own expense with

all dispatch, always provided that the Engineer may first permit further tests, at the

contractor’s expense, to prove the quality of the deposited concrete.

In the case of seven day Works Cube Tests providing unsatisfactory, the works may be

stopped, but shall not be liable to rejection until the result of the twenty eight day test

is known.

In the event of the results of the twenty eight day works Cube Tests proving

unsatisfactory, the work represented shall be immediately liable to rejection. The

contractor may, however, be given the option of cutting three specimens from the

completed work subject to the direction of the Engineer, and preparing therefrom test

cubes or cores which shall be sent to the Test Laboratory for testing as for Works Cubes

Tests.

Should the average strength of these specimens attain the specified minimum twenty

eight day strength, the work will, subject to the Engineer’s discretion, be accepted.

Alternatively, the Engineer may instruct the Contractor to make a loading test as

described hereinafter. The cost of all cutting, preparation of specimens, testing and

making good the portions of the structure affected, shall be borne by the Contractor. The

cost of all delays on site investigation of defects, cutting away and making good, shall

be entirely the Contractor’s responsibility.

A. DAMAGED OR UNSATISFACTORY MATERIALS

All materials, which have been damaged, contaminated or have deteriorated, or which do

not comply in any way with the requirement of the specification, shall be rejected and

shall be immediately removed from site.

No materials shall be stored or stacked on suspended floors without the Architect’s prior

approval.

Should any of the samples tested be found, in the opinion of the Engineer, in any respect

unsatisfactory or likely to produce unsound work, the whole consignment or load from

which samples were taken will be rejected, and the Contractor shall forthwith remove it

from site. Notwithstanding that any sample of the material may have passed the test,

the Engineer may later reject such consignment or loads if he shall decide that the quality

has deteriorated.

The Contractor at his own expense shall remove from the site, without delay, all rejected

material. Any delay caused by such rejection will not in any way relieve the Contractor

from his responsibility with regard to the completion within the time limit (s) specified.

Any bag of cement that is opened shall be used on the same day or be discarded from

the work.

B. COMPOSITE SUSPENDED SLABS

Concrete hollow pots

Concrete hollow pots for use in the composition floor slabs are to be of the sizes required

as shown on the drawings and with 25mm wall thickness and are to be true to shape, free

from cracks or distortion of adequate strength to support the concrete during placing and

consolidation by vibration. Stock are to be manufactured in accordance with the

procedure specified in B.S. 2028 and to be of mix not weaker than 1:4:8 cement: sand:

aggregate using maximum 10mm size aggregate.

Concrete hollow pots are to be cured for at least 28 days before use on the site. During

the first seven days of curing, pots are to be kept permanently damp and protected

from exposure to sun and wind.

Hollow clay pots

Hollow clay pots where indicated for use in the composite floor slabs, are to be the sizes

shown on the drawings and to be of adequate strength to support the concrete during

placing and consolidation by vibration. They shall be obtained from an approved

manufacturer. Before any orders are placed, at least 6 sample clay blocks shall be

provided for the approval of the Engineer.

Hollow clay pots (cont’d)

Any clay blocks subsequently delivered to site which in he opinion of the Engineer are

not of equal standard to the approval samples shall be rejected.

Rejected pots shall immediately be removed from the site and shall not be used in the

works. Clay blocks are to be fully cured before delivery or use on site.

Defective or damaged pots are to be removed immediately from the site.

Generally

The hollow pot floor construction is generally to be as shown on the Engineer’s

drawings.

Care shall be taken in placing pots to ensure that they are set out in accordance with the

details shown on the Drawings and that they run truly in line without encroaching on the

width of the insitu concrete ribs.

The open ends of hollow pots, if adjacent to concrete to be placed insitu, are to be

plugged or stopped to prevent the concrete from flowing into the void and the contractor

is to include for this in his prices.

Before concreting is carried out the pots are to be thoroughly wetted.

Care should be taken during concreting that the width of ribs between the rows of pots

and the solid insitu concrete shown on the Drawings adjacent to stopping beams is not

encroached upon by the pots.

Where holes for services occur, the necessary holes or pockets shall be accommodated by

the replacing of a hollow pot by insitu concrete or the widening of a rib.

Prices for such holes through hollow pot slab construction are to include for the re-

arrangement or substitution of the hollow pot with solid concrete in addition to the actual

formation of the hole.

The concrete topping shall be poured at the same time as the ribs between hollow pots.

Reinforcement shall be positioned accurately with the specified cover in accordance with

the Drawings and using the particular spacer blocks as previously described

Spacer blocks shall be provided at not more than 1200mm centres.

Care must be taken during concreting that the reinforcement is not displaced.

WORKMANSHIP

A. PLANT AND METHOD

Before the commencement of any work, the Contractor shall submit the following for

the Engineer’s written approval:

(i) The concreting method, including the size and type of machines for

weighing and mixing concrete and the methods of transporting, placing and

compacting.

(ii) Details of formwork proposals, clearly indicating the general method of

construction and assembly, the method of achieving surface finishes

required herein, including lining, fixing of linings together with positions

of joints and the make and type of mould oil proposed.

(iii) The proposed position and type of every construction joint not already

shown of the Engineer’s drawings.

Such approval by the Engineer shall not be deemed to relieve the contractor of his

obligations to comply-with any of the provisions herein.

Concrete mixing and discharge from mixers shall be under permanent cover to the

Engineer’s approval.

B. MEASUREMENT AND MIXING

All cement is to be measured by weight, the 50kg. Bag of cement being used as a unit.

The amount of water shall be the minimum required to produce dense cohesive concrete

of adequate workability to be determined by trial mixes. This amount shall be accurately

gauged and adjusted from time to time to compensate for variations in moisture content to

the aggregates by an approved method

All concrete shall be mixed in a batch type mechanical mixer of approved type having a

drum rotating about a horizontal or inclined axis. The speed of the drum is to be not more

that twenty and not less than fourteen revolutions per minute.

Each mixer is to be fitted with a water measuring device capable of accurate measurement

to one gallon for one cubic yard mixers and prorata for smaller sizes and so arranged that

the accuracy is not affected by variations in the pressure of the water supply line. The

fine and coarse aggregate and the cement shall be mixed for at least four turns, after

which the required amount of water shall be added gradually while the mixer is in motion

and the concrete mixed for not less than one half minutes to a uniform colour and

consistency.

The volume of concrete mixed in any one batch is not to exceed the rated capacity of the

mixer.

The whole of the mixed batch is to be removed before materials for fresh batch enter the

drum.

Concrete as mixed in accordance with the foregoing shall not be modified by the addition

of further water or in any other manner on the cessation of work, including all stoppages

exceeding twenty minutes or any change of cement used in the mix, the mixer, and all

handling plant shall be washed out with clean water. At least one slump test shall be

made each day concreting is in progress under the supervision of the Engineer.

A. REINFORCEMENT

Reinforcement shall be free from all loose scale, loose rust, oil grease or similar defects,

immediately before placing the concrete. It shall be bent cold exactly to detail using

an approved bending machine. Hooks, bends, etc., where not specifically detailed, are to

be in accordance with B.S. 4461. Each bundle of bent bars shall be clearly tagged with

the bar list number.

Reinforcement shall be placed in the exact position shown on drawings with all inter-

sections tacked welded or securely tied with 16 gauge soft steel tying wire. The

designated cover shall be maintained by approved spacers, stools, bolsters or ties fixed to

the reinforcement. There shall be dense concrete left with a wire brushed surface or be

dipped in grout before fixing. These blocks are particularly important where the surface

of the concrete is exposed to weather or dampness. The Contractor must ensure that

bars are securely fixed so as to maintain their indicated positions during progress of

pouring, tamping or vibration of concrete. Six tools are to be provided around each

column to hold top steel in position and are to be made up of mild steel bars of

adequate diameter. The cost of providing and fixing these steel stools must be allowed

for by the Contractor in his rates for reinforcement generally. No laps or splices in bars

shall be made without prior approval of the Engineer except those detailed on the

drawings. The size and position of the reinforcement bars or mesh shall be approved by

the Engineer before concreting commences.

The insertion of reinforcement into concrete already placed, the lengthening of bars by

welding and the rebending of incorrectly bent bars will not be permitted.

For concrete having exposed surfaces, reinforcement shall be assembled and placed in

such a manner as to avoid any damage to formwork faces.

Where reinforced concrete slabs or walls are constructed against tanking, care shall be

taken in positioning reinforcement to avoid damage to tanking.

Unless otherwise shown upon the Engineer’s drawings, or specified in B.S. CP114, the

reinforcement bars shall be given the following cover of concrete:-

In floor slabs, walls and similar thin panelling, a cover of 13mm or the

size of the bar, whichever is the greater. In beams and other such

members, a cover of concrete of 25mm to the main reinforcement or the

size of the bar whichever is greater.

In columns a cover of concrete of 40mm to main reinforcement the size of

the bar, whichever is greater.

In foundations and column bases, a cover of 50mm to main reinforcement,

or the size of the bar, whichever is greater.

A. INSPECTION OF REINFROCEMENT

When the placing of reinforcement for a particular section of the works is completed and

before concreting commences, the reinforcement will be inspected by the Engineer and

no concrete shall be placed until the Engineer’s approval has been given. The Contractor

shall give the Engineer 48 hours notice of the time when the reinforcement will be ready

for inspection. Where the distance of the site of the Works is more than 100 kilometres

from the nearest office of the Engineer, this time shall be increased to 96 hours.

B. FORMWORK

Formwork shall be true to line, level face and profile and be of robust construction

adequately framed, braced, strutted, cramped, tied and propped to restrict deformation

due to construction loads to not more that 3mm, and to entirely eliminate deformation of

the form faces by warping or buckling. Wire ties will not be permitted. Formwork shall

be grout-tight under all conditions including vibration when specified or used.

Formwork shall be designed to allow prefabrication of conveniently sized elements to

facilitate ease of handling and assembly, to permit striking without force, shock or

any damage whatsoever to the concrete member or formwork face and permit the removal

of sides without disturbing soffits. Propping shall be carried down to an approved

bearing, shall not be supported by timber floors and shall be arranged that formwork

may be lowered smoothly.

Repropping will not be permitted. Provision shall be made for cleaning out and draining.

Formwork shall be constructed of material or lined with material as may be necessary to

achieve the finishes specified herein and in such a manner as to eliminate screw or nail

head imperfections.

Before each use, Formwork faces shall be treated with the minimum amount of an

approved mould oil necessary to obtain a clean release. Mould oil shall not come into

contact with the reinforcement.

The use of cement retarders will not be permitted except where a key for or other finishes

is required.

Before placing of the concrete, bolts and fixing shall be in position and cores and other

devices used for forming openings, holes, pockets, recesses, ducts or other cavities shall

be fixed to the shuttering.

Immediately prior to concreting, formwork shall be thoroughly cleaned out and

formwork and given his consent for concreting to proceed but such consent shall not

relieve the Contractor of his responsibility for its sufficiency. After striking, formwork

shall be cleaned, stacked and protected and before re-use, shall be serviced, made good

or replaced with new as may be necessary to maintain the finish and the standard

specified.

A. TOLERANCES

The maximum tolerances within which concrete work shall be constructed are as

follows:-

1. All setting out dimensions, and dimensions horizontally and

Vertically. + 5 mm

2. Section of concrete member + 15mm

3. Levels of floor slabs, beams, lintels etc. + 5 mm

4. Plumb of columns and walls in storey height + 5 mm

5. Plumb of columns and wall in full building height + 20 mm

6. Inside faces of life shafts in storey height + 5 mm

7. Inside faces of lift shafts in full building height + 15 mm

8. Concrete cover to reinforcement + 3 mm

No surfaces intended to be horizontal or vertical shall slope more than 2mm in l metre.

Any rectification of work not constructed within the tolerances set out above shall be

entirely at the responsibility and expense of the Contractor.

B. PLACING AND COMPACTION

No traffic whatsoever, wheeled or foot, shall take place over reinforcement placed

concrete and the Contractor shall provide all necessary stools, walkways, platforms and

barrow runs. Concrete shall be placed in its final position as rapidly as practicable by

methods which preclude segregation or loss of ingredients and in any case, within 30

minutes from the time that water is added to the mix; compaction shall be completed

before initial set commences. Partially set concrete shall not be re-worked or used.

Flowing in formwork shall be avoided by placing and compacting in shallow layers in

quick succession.

The workability of the concrete must never be altered by the use of additional water or

sand alone.

Foundations shall be placed their full depth in one operation and the top surface carefully

levelled. Concrete placed in timbered excavations shall be well rammed close against the

excavation face as the timber is withdrawn.

Where the design of the work demands the placing of reinforced concrete against the

sides of excavation without the use of formwork, the earth face in such locations shall

be prevented from crumbling or washing into concrete during placing and compaction

by any efficient means, and care shall be taken to maintain the correct cover to the

reinforcement.

All concreting shall be continuous to completion or to an approved construction joint.

Methods of placing and vibrating generally are to comply with the specifications for

vibrated concrete as laid down by the manufacturer of the vibrators used on the works.

During placing of all concrete a workman shall be in constant attendance with a hose pipe

to wash off any cement slurry which appears on the face of any previously poured

concrete immediately it occurs.

Concrete shall be placed into the forms from as less a height as possible and shall in no

case be dropped from a height of more than 1500mm except with the approval of the

Engineer.

When chuting is used, the inclination of the chute must be such as to allow the concrete to

flow without the use of excessive water and without segregation or loss of the ingredients.

Details of any proposed chuting plant must be approved by the Engineer before the plant

is delivered to the site.

If the Contractor wishes to distribute concrete by means of pumps, full details of the

system must be made available to the Engineer for approval.

Concrete shall be thoroughly compacted and carefully worked with suitable tools, into

formwork and around reinforcement and fixtures so as to avoid displacement. A

competent steel fixer shall attend throughout concreting to correct any unavoidable

displacement. Compaction shall be by means of vibrators; these shall be of an approved

pattern, of the immersion type; clamp on external vibrators, in adequate numbers shall be

used only where the density o reinforcement precludes immersion.

Attachments to reinforcement are expressly forbidden and accidental contact with

reinforcement shall be avoided. Vibration shall be executed by a competent operative

and shall not be carried out to the detriment of adjacent partly hardened concrete.

An accurate schedule is to be kept by the contractor showing dates and times when

various portions of the work were concreted. The concreting foreman must not vary the

approved mix or water content without the permission of the representative of the

Engineer. It may occasionally be found that in concreted members or where the

proportion of reinforcement in concrete is high, the workability of the concrete must be

increased especially in order to effect full compaction. Such increase in workability shall

be achieved by an increase in the mortar content of not more than 10% of the concrete

by weight in any single batch and must be made only with the approval of the

representative of the Engineer.

A. COLUMN PLINTHS

Column kicker plinths not cast monolithically with the beam or slab will be allowed only

at the discretion of the Engineer and special precautions must be taken if permission is

granted especially in regard to the quality of the mix used, and the curing of the concrete.

B. BLINDING CONCRETE

No casting of any concrete on the ground shall take place until the ground has been

passed as satisfactory by the Engineer. All ground to carry reinforced concrete shall be

covered with a blinding layer of a specified quality of concrete of the thickness shown on

the drawings or if not so shown a minimum of 50mm.

A. WATERPROOF CONCRETE

Whenever waterproof concrete is shown on the drawing it shall be mix 1:1 ½ : 3 nominal

and it shall be compacted by mechanical vibration so that a dense and homogenous mass

of concrete is obtained throughout every pour of the structure, all in accordance with

C.P. 2007.

The Contractor shall be allowed at his own cost to add an approved waterproofing

additive to the mix using it strictly in accordance with the maker’s printed instructions.

All permanent and construction joints shall be constructed in accordance with the

drawings and specifications to achieve complete water tightness.

It shall be the Contractor’s responsibility to ensure that all structures required to be

constructed in waterproof concrete are completely watertight and any work found to be

defective shall be made good to the Engineer’s satisfaction at the Contractor’s expense.

Where waterproof concrete forms a water retaining structure it is to be tested by filling with

water for a period of not less than four days. Any percolation or porous concrete or leaking

joint is to be made good at the Contractor’s expense. Tanks and pools constructed below

ground level are not to be backfield prior to the satisfactory completion of this test.

B. CONSTRUCTION JOINTS

All construction joints shall be straight, truly vertical or level, as the case may be, of

profile shown and formed in the exact positions shown on drawings or if not shown on

the drawings, with prior approval of the Engineer. Vertical joints shall be formed against

adequately secured rigid stop boards having splayed fillets, designed to pass the continuos

steel reinforcement without temporary bending or displacement.

The rate and method of placing concrete and the arrangement of joint bulkheads shall be

such that the concrete between construction joints shall be placed in a continous

operation.

Joints in reinforced slabs and beams, shall be perpendicular to the axis or surface of the

member jointed and at one third of the span. If an intersecting member occursat that

point, the joint shall be located at a point of minimum shear.

Construction joint in columns shall be as shown on the drawings. Wherever it becomes

necessary to stop work, such stops shall be located at one third span of slab and beams or

as directed by the Engineer.

An adequate and acceptable key of a succeeding work shall be formed by using stop

boards, which shall be constructed tightly to prevent any grout leak. As early as possible

boards shall be removed and the surface thoroughly hacked and brushed to remove all

laitence. Any leakage past stop boards shall be hacked off as soon as the concrete has

set. The surface shall be left clean and dry. Immediately prior to further concreting the

joint face shall be soaked with water and covered with sand cement mortar of proportions

identical to that in the concrete to be placed, punned into the body of the set concrete.

For exposed finishes, care shall be exercised to preserve an unbroken line at the exposed

edge of the joint.

In no circumstances shall the concrete be allowed to finish at a break running down a

rough slope. Such cases, if found, will be treated as contrary to the specification and

the Contractor will be required to cut out the member and re-cast. In the case of

horizontal joints, any excess water and laitance shall be removed from the surface after

the concrete is deposited and before it has set.

Before casting slabs the hauchings or seatings for the slab shall be thoroughly hacked,

scored and washed and covered with at least 5mm of mortar immediately before the

slab is cast.

Any necessary construction joints in foundations shall be stepped and lapped 600mm

joint faces shall be prepared and treated as described above.

A. STRIKING TIMES

It shall be the Contractor’s responsibility that no distortion, damage, overloading or undue

deflection is caused to the structure by the striking of formwork, but the Engineer

reserves the right to delay the time of striking in the interest of the work. Formwork

shall not be struck until the concrete has sufficiently hardened. Approval of the

Engineer shall not relieve the Contractor of his liability to make good any concrete

damaged by premature removal or collapse of forms. In no circumstances shall forms

be struck until concrete reaches a cube strength of at least twice the stress to

which the concrete may be subjected at the time of striking. The following striking times

given in days (24 hours) are the absolute minimum that will be permitted:-

Forms Ordinary Rapid

Portland Hardening

Cement Cement

Walls

Columns (Unloaded) 2 2

Beam sides

Slabs – props left under 7 2

Beam soffits – props

Left under 14 5

Slab – props 14 5

Beams – props 21 8

The time for removal of forms as cut shall not apply to slabs and beams spanning

more than 10 metres. For such spans appropriate times shall be recommended

or advised by the Engineer.

Where the structure is of multi storey construction props with head trees and

braces shall be provided to distribute the imposed load below the floor being

cast. This will be at least 2 storey heights below the floor being cast unless

otherwise stated.

A. CURING

The curing of the concrete must receive particular careful attention. The concrete shall

be covered with a layer of sacking, canvas, hessian or suitable absorbent material, and

concrete, formwork and covering kept constantly wet for the first seven days after casting.

B. MIXES, CHASES AND CASTING IN

No holes or chases are to be cut in reinforced concrete works. The contractor shall ensure

that all necessary holes and chases, including fixing holes for railings and balustrades etc.,

are carefully formed in the correct position by requisite measures prior to the placing of

concrete.

All conduits, pipes, tubes and the like shall unless otherwise detailed, be run on top of

the bottom reinforcement of the concrete work. It shall be the Contractor’s responsibility

to ensure full co-ordination with Sub-Contractors in the setting out for this purpose.

Generally, conduits, pipes and special fixtures shall be concreted in where required and

in the exact positions demanded.

Details of the positions of all holes, chases and fixing blocks shall be submitted to the

Engineer for his approval prior to putting the work in hand.

C. TESTS OF COMPLETE STRUCTURAL MEMBERS

The Engineer shall instruct that a loading test be made on the Works, or any part

thereof, if in his opinion such a test be deemed necessary for one or more of the

following reasons:-

(a) The site-made concrete tube cubes failing to attain the specified strength.

(b) The shuttering being prematurely removed.

(c) Overloading during construction of works, or part thereof.

(d) Concrete improperly cured.

(e) Any other circumstances attributable to negligence on the past of the

Contractor which, in the opinion of the Engineer, may result in the works,

or part thereof, being less than the required strength.

If the loading test be instructed to be made solely, or in part, for one or more of the

reasons mentioned above, the tests shall be made at the Contractor’s own cost. If a test

be instructed to be made for any other reason than specifically stated above, the

Contractor shall make the test and shall be reimbursed for all costs relating thereto.

Loading tests are to be conformity with Clause 605 of British Standard Code of Practice

CP 114.

If the result of the loading test be not satisfactory, the Engineer shall instruct thatthe part

of the works concerned shall be taken down or removed and reconstructed to comply with

this specification, or that such other remedial measures shall be taken as to make the work

secure.

If the tests be instructed to be made for one or more of the reasons (a) to (e) inclusive as

herein before specified, the Contractor shall take down or remove and reconstruct the

defective work, or shall take the remedial measures instructed all at his own cost.

A. PROTECTION

All insitu and precast concrete shall be protected from rain and during hot, dry and windy

weather approved hessian covering kept constantly damp shall be used to prevent

premature drying out.

All insitu and precast concrete shall be protected from damage by disturbance, shock

vibrations, early loading or overloading. In addition, all exposed finishes shall be

constantly protected from mechanical damage to arises or faces and damage due to

dropping, splashing and staining from any source including rusty scaffolding or

reinforcement.

No materials or equipment of any kind shall be stored or stacked on suspended floors

without the Engineer’s prior approval.

B. PRECAST CONCRETE

Precast concrete lintels shall comply with B.S. 1239.

Precast concrete kerbs shall comply with B.S. 340, figure 5

Concrete shall all be cast in properly made strong moulds to form shapes required.

For work described as “finished fair” the mould shall be lined with sheet or other

approved material to give the required surface finishes.

The coarse aggregate for precast concrete shall be 10mm gauge for mix specified.

The concrete shall be of the mixes described and shall be thoroughly tamped in the

moulds and shall not be removed from them until seven days after placing the

concrete, but the sides may be removed after three days providing the moulds are

such that the sides are easily removable without damaging the concrete.

The precast work shall be cast under sheds and shall remain under same for seven

days in the moulds and a further seven days after removal the moulds. During the

whole of this period the concrete shall e shielded by sacking or other approved

material kept wet. It shall then be removed from the sheds and stacked in the open

for at least seven days to season.

Precast concrete units shall be true and smooth on all faces (except where a key is

required for applied finishes). All arises shall be true and clean with no broken

edges.

All units shall be marked during manufacture to indicate

(a) The date of casting

(b) Identification lettering in accordance with the drawings

(c) Where necessary, the way up for building in.

Ends of bar reinforcement shall be 25mm from internal faces and 40mm from

external faces. Nominally non reinforced units may contain reinforcement at the

Contractor’s option for handling purposes, the cost of which shall be deemed to be

included in the pricing.

A. SURFACE FINISHES

After removal of shuttering, unless instructed to the contrary, the face of exposed

concrete is to be rubbed down immediately to remove fins or other irregularities. In

the event of parts of the concrete being honeycombed, such portions are to be cut to

depth and shape required b the Engineer and made up with fine concrete of equal

quality in such a manner as shall be directed. The face of concrete for which

shuttering is not provided, other than slabs, is to be smoothed with a wooded float to

give a finish equal to that of the rubbed-down surface where shuttering is provided.

The top face of slab which is not intended to cover with other material is to be

levelled and floated before setting to a smooth finish at the levels or falls shown on

the drawings or elsewhere.

The floating must be carried out in such a way as will prevent an excess of mortar

being brought to the surface of the concrete. The top face of a slab intended to be

surfaces with mortar, granolithic or similar material is to be brushed with a stiff

broom while still green to remove any laitance and provide a roughened surface.

(a) Samples Before the execution of any specified finish, the Contractor shall

prepare 1200mm square samples for the Architect’s approval.

No concreting in finish work shall be attempted until after the approval of a sample.

Approved samples shall be retained till the completion of all such work and closely

adhered to throughout the work. Rejected samples shall be demolished and removed.

(b) Rendered or plastered surfaces Concrete surfaces to be rendered or plastered

shall be thoroughly hacked to form a good key.

(c) Fair faced surfaces Fair faced surfaces shall be free from honeycombing,

stains, fins, lippings, nails holes or excessive air holes and shall be of a uniform

colour and texture. This surface shall be obtained by the use of.

(i) Wrot forms, i.e. timber forms planed smooth on the surfaces in contact with

concrete

(ii) Forms lined with hardwood or plywood or other approved material,

or

(iii) Smooth steel forms.

B. PRICING NOTES

The Contractor must allow for all costs incurred during the progress of the Contract for

complying with the provisions concerning the preparation of graded mixes.

Prices for concrete slabs shall include for all temporary formwork to form construction

joints at bay edges.

Prices for reinforced concrete shall include for filling into, between or on formwork and

thoroughly compacting between and around rods or fabric reinforcement and for forming

all additional construction joints between varying mixes.

Formwork is measured net to the actual face of the concrete to be supported and the

prices for formwork shall include for the extra material at joints, extra labour and waste

for narrow widths small quantities, overlaps, passings at angles, straight cutting and waste

splayed edges, notchings, etc., and for fixing at the various levels including battens,

struts, and supports and for bolting, wedging, easing, striking and removal Prices for

lineal items such as bocing shall include for angles and ends.

Prices for fabric reinforcement shall include for all straight cutting and waste, and

temporary support and all extra material in laps.

Prices of all precast concrete shall include for all moulds, finishing as described, hoisting

and fixing at the required levels, bedding, jointing and pointing in cement and sand

mortar, also for casting or cutting to the exact lengths required and any waste resulting

from such cutting. The sizes of weathered or moulded items stated are extreme sizes.

Prices for hollow block suspended slabs shall include for concrete filling run into the

open ends of blocks or blind end blocks.

Prices for expansion joints shall include for cutting to size and all temporary supports and

prices for expansion joint sealers shall include for all temporary battens or fillets

required to form the necessary grooves.

WALLING

MATERIALS

A. CEMENT

Cement used for making mortar shall be as described in “Concrete Work”.

B. LIME

The lime for making mortar shall comply with B.S. 890 Class A for non-hydraulic lime.

The lime to be run to putty in an approved lined pit or container.

The water to be first run into the pit or container and the lime to be added until it is

completely submerged, stirred vigorously until all lumps are disintegrated and shall be

kept constantly covered with water and regularly stirred for at least four weeks. The

resulting milk-lime then to be run through a fine sieve and run into a pit or other

container and kept clean and moist for not less than two weeks before being used in the

works.

C. SAND

Sand used for making mortar shall be clean well graded siliceous sand of good sharp hard

quality equal to samples which shall be deposited with and approved by the Architect. It

shall be free from lumps of stone, earth loam, dust, salt, organic matter and other

deleterious substance, passed through by the Architect sieve and washed with clean water

if directed by the Architect.

A. WATER

Shall be as described in “Concrete work.”

B. CONCRETE BLOCKS

Solid and hollow concrete blocks for walling shall comply with B.S. 2028 Type “A’ and

“B”, and the minimum compressive strengths given hereafter refer to table 2 of that B.S.

They are to be equal in every respect to a sample to be deposited with and approved by

the Architect. Walling is to be built in 200mm courses that is 190mm block h eight

plus a 10mm joint and of the thickness given herein.

They shall be hard, true to size, shape and with sharp arrises. For work below first floor

slab, blocks to be Type A7, All other blockwork to be Type B7.

They shall be obtained from an approved manufacturer or manufactured on site in

approved block-making machines. The mix used shall be not less than 1:9 by volume and

the maximum size of aggregate shall be 12mm size.

The blocks, on removal from the machine, shall be carefully laid on edge or racks under

sheds erected by the Contractor and left for 3 days during which period they hall be kept

constantly wet after which they shall be placed on edge in the open racks and protected by

sacking or other approved covering and kept wet for a further 5 days.

Thereafter, the blocks shall be left in the same position without wetting for a further 20

days.

No blocks will be allowed to be used in the works until 28 days old and until samples

have been tested and approved by the Engineer.

The Contractor is to ensure that blocks are stocked separately in their respective

categories and used in the structure in the positions shown on the drawings.

TABLE 2. COMPRESSIVE STRENGTH OF TYPE A AND B BLOCKS

Block

Type and

designation

Minimum compressive strength

Average of 10 blocks

Lowest individual block

A(3.5)

A(7)

A(10.5

A(14)

A(21)

A(28)

A(35)

N/mm2*

(MPa)*

3.5

7.0

10.5

14.0

21.0

28.0

35.0

Ibf/in2

500

1000

1500

2000

3000

4000

5000

N/mm2

(MPa)*

2.8

5.6

8.4

11.2

16.8

22.4

28.0

Ibf/in2

400

800

1200

1600

2400

3200

4000

B(2.8)

B(7)

2.8

7.0

400

1000

2.25

5.6

320

800

A. HOLLOW CLAY BLOCKS

Hollow clay blocks to comply with the provisions of B.S. 1190 section I, are to be hard

well burnt true to size shape and with sharp arrises and keyed faces and joints and

are to be obtained from an approved manufacturer and to be equal in every respect to a

sample to be deposited with and approved by the Architect. Blocks are to be 190mm

high (to give 200mm course height including the joint) and of the thicknesses given

herein. Cutting of blocks is to be avoided wherever possible and full use is to be made

of quarter, half and three quarter blocks, and blocks with conduit recesses.

B. STONE

Stone shall be sound and hard and free from all defects and shall be as approved by the

Architect.

All stone required for walling (unless otherwise described) shall be chisel dressed into

true rectangular blocks with each surface even and at right angles to all adjoining

surfaces. Ordinary walling shall be built 190mm courses, and of the thickness

given herein with all dimensions having a tolerance of plus or minus 6mm. At

least 80% of all stone blocks shall be not less than 500mm in length and no block will

be allowed to be cut or redressed after it is built into the work.

C. CLAY GRILLERS

To be from an approved manufacturer, hard, well burnt, true to shape and size and equal

in all respects to samples to be deposited with and approved by the Architect. Grilles to

be built in regular courses with vertical joints straight and true.

D. FACING BRICKS AND TILES

Clay facing bricks and tiles, shall be obtained from an approved manufacturer and shall

match in all respects a sample deposited with and approved by the Architect.

E. CORAL

(i) Coral shall be sound and hard and may be selected from materials arising

from the excavations if approved by the Architect.

(ii) Coursed Coral for walling (unless otherwise described) shall be chisel

dressed into true rectangular blocks with each surface even and at right

angles to all adjoining surfaces. Ordinary walling shall be built in 190mm

courses, and of nominal 100mm, 140mm, 150mm, 190mm, 230mm

thickness with all dimensions having a tolerance of plus or minus 6mm. At

least 80% of al coral blocks shall be not less than 510mm in length and no

block will be allowed to be cut or redressed after it is built into the work.

(iii) Where described as coral rag the stones shall be irregularly shaped and

selected for soundness, colour and texture and roughly hammer dressed if

required. The finished face is to be left absolutely free from mortar and

other smears and blemishes.

A. WALL REINFORCEMENT

Walls less than 200mm shall be reinforced with a 25mm wide strip of 16 gauge thick

hoop iron built into alternate horizontal joints in the wall centre. The reinforcement shall

be lapped and hooked at running joints, angles and intersections and carried at least

115mm into abutting walls at junctions.

B. WALL TIES

To be 3mm diameter galvanised mild steel wire twisted butterfly wall ties.

C. DAMP PROOF COURSE

To be asbestos base fully bitumen impregnated in accordance with B.S. 743 weighing not

less than 3.80 kgs. Per square metre. The sheeting is to be lapped 150mm at running

joints and the full width of walls at angles.

WORKMANSHIP

D. CEMENT MORTAR

Mortar described as cement mortar 1:5 shall be composed of 1 cubic metre

(1442kgs.) of Portland cement to 5 cubic metres of sand. Other mixes such as 1:3, 1:4,

shall be similarly construed.

E. CEMENT LIME MORTAR

Mortar described as cement lime mortar 1:1:4 shall be composed of 1 cubic metre (1442

kgs.) of cement and 1 cubic metres of lime and 4 cubic metres of sand. Other mixes shall

be similarly construed.

F. MIXING OF MORTARS

The constituent materials shall be measured separately when dry in specially prepared

gauge boxes of sizes to give the proportions specified without consolidation of

the contents by ramming and shaking. The mortar shall be mixed in an approved power

driven mixer for not less than two minutes per batch and using the minimum

quantity of water necessary to obtain a working constituency. The mixer shall be

used as close as practicable to the works and mortar shall be used within 30 minutes

of mixing. No partially or wholly set mortar will be allowed to be used or re-mixed.

G. GENERAL CONSTRUCTION

(a) Setting Out. The Contractor shall provide proper setting out rods and set out

all work on same for courses, openings, heights, etc., and shall build the wall,

piers, etc., to the widths, depths and heights indicated on the Drawings and as

directed by the Architect.

(b) Building in Wood Frames. Openings for doors ventilator, etc., are to be set

out and left unbuilt until the wooded frames have been fixed in position.

(c) Building in Metal Windows and Doors openings. For metal frames are to be

wide enough for the frames to fit without being forced into position. Build the

lugs into the joints of the walling and fill in the space between the walling and

frame with cement mortar 1:5 well tamped into the channel of the frames

and point all round externally.

All frames must be set plumb and level and free from twists.

(d) Walls to receive Plaster and similar finishes. All faces of walls to be

plastered, etc., to have all projections dressed off and joints raked out as

key.

A. BUILDING WALLING

(a) Laying and jointing. All blocks shall be well wetted before being laid and

the top of walling where left off shall be well wetted before recommencing

building. Walls throughout the Works shall be carried up evenly in

200mm courses except where courses of less depth are required to bring

walling up to level of floors, windows and the like and where otherwise

described, no part being allowed to be carried up more than one metre

higher at one time than any other part and in such cases the joining shall be

made in long steps so as to prevent cracks arising and all walls shall be

levelled round at each stage.

Blocks shall be bedded and jointed in cement mortar (1:5) as described

with beds and joints 10mm thick, all flushed up and grouted solid as

the work proceeds.

All walling shall be properly protected and kept wet for three days after

Building.

(b) Bonding The blocks shall be properly bonded together and in such

manner that no vertical joint in any one course shall be within 115mm of a

similar joint in the courses immediately above or below. All walling of

300mm thickness or less shall be built in single thickness of blocks.

Walling exceeding 300mm in thickness shall be built with through bonders

not more than 1070mm apart in each course as directed by the Architect.

Alternate courses of walling at all angles and intersection shall be carried through the

full thickness of the adjoining wall. All perpends, reveals and other angles of the

walling shall be built strictly true and square.

Alternate courses in attached piers, etc., to be of single blocks and the vertical joints in

alternate courses to midway between back and front faces.

B. FAIR FACE

All concrete and hollow clay blockwork described as finish with a fair face is to be built

to a true and even face with the joints finished as specified hereinafter.

C. BRICK AND TILE FACING

(a) All brick and tile facework shall be set out and built to the respective

dimensions, thickness and heights shown on the drawings. The bricks or

tiles shall be well laid with 6mm joints and pointed with neat weathered

joints as the work proceeds.

(b) A sample panel about 1 metre square of each of the facings is to be

constructed on the site and when approved by the Architect shall be

retained as the Standard for the Works and cleared away on completion all

at the expense o the contractor.

A. HOLES CUTTING AND CHASING

(a) All putlog holes shall be not less than one course deep and carefully filled with

a block cut to fit size of opening with beds and joints filled in with mortar well

tamped in after scaffolding is removed, and if in faced walls, to match

facings.

(b) Where walling is cut, holed or chased for conduits’ pipes and the like all such

cuttings, etc., shall be filled in with cement mortar (1:4) prior to the application of

finishes.

B. CORAL RAG FACING

Coral rag facing shall consist of irregularly shaped stones rough hammer dressed to a

50mm thickness and bedded against concrete block walling and pointed in cement and

sand (1:5) mortar. The finished face is to be free from mortar stains and wire

brushed.

C. LOUVRE BLOCK WALLING

(i) To be precast concrete Grade “20” with 10mm aggregate finished fair on

all exposed surfaces and built in cement mortar (1:5) with straight

horizontal and vertical joints and flush pointed both sides.

(ii) Each block size 200mm x 400mm long x 200mm high and consisting of

two ends each 200mm x 200mm x 50mm thick joined with 50mm thick

twice cranked louvre with top end of louvre projecting 40mm above top of

block.

D. PRICING NOTES

Price for all walling shall include for normal rough and straight cutting, plumbing angles,

all cutting and waste and split courses necessary for bond, bonding at angles intersections

and junctions of all thicknesses, split courses, cutting and pinning up to columns beams

slabs, etc., cutting and pinning in ends of cills, lintels, beams etc. Forming all openings

and reveals to same and all cutting and waste to walling in short lengths such as mullions

unless specifically measured.

Prices for all walling shall include for hoisting and building off beams and slabs at any

level and work built over-hand.

Prices for hollow block walling must further include for all necessary solid blocks or fine

concrete filing to open ends of blocks at intersections, ends and angles of walling.

ASPHALT WORK

E. Generally

All asphalt is to be manufactured and applied strictly in accordance with the appropriate

B.S. or C.P. as stated hereafter.

F. COLD APPLIED ASPHALT (COLAS)

Shall be as manufactured by Ms. Colas East Africa Ltd of P. O. Box 46644 Nairobi, or other

equal and approved manufacturer and applied in accordance with manufacturer’s written

instructions.

BASE TANKING AND DAMP-PROOF COURSES

A. Materials and Workmanship

Mastic asphalt to comply with B.S. 1162, subsection 1418 (natural rock asphalt

aggregate) or B.S. 1415 (limestone aggregate) and to be laid in accordance with C.P.

110 “Protection of Buildings against Water from the Ground”

B. Basement damp-proof course

Lay over the whole area of the basement floor on concrete bed horizontal damp-proof

course in three thickness laid with 150mm laps to a total thickness of 30mm and carried

through walls to connect with vertical damp proof course with a two-coat angle fillet.

C. Vertical damp-proof course to basement

Cover outer face of basement walls with a vertical damp-proof course applied in three

thicknesses with 75mm laps to a total thickness of not less than 20mm. To be carried up

to a minimum height of 150mm above ground level and connected to horizontal damp

proof course in walls to form a complete tank to basement.

D. Column reinforcement

Ensure that a good, tight joint is made to column reinforcement where projecting through

basement slab and that thickness of asphalt is maintained at these junctions.

E. Basement asphalt protection

Immediately following the laying of the basement asphalt provide and lay over the whole

of the basement area a fine concrete screed as specified to minimum thickness of 50mm.

F. Water level

Maintain the water level at not less than 300mm below the level of the basement slab

concrete during the progress of the tanking work to avoid application of asphalt to wet

surfaces. Pumping operations are to continue until the temporary sump has been filled

and sealed.

G. Back filling

When back filling to basement ensure that the nature of the fill is such that the vertical

damp proof course will not be damaged or punctured and that the pressure exerted

against the vertical damp proof course will not cause the asphalt to squeeze out.

H. Horizontal damp-proof course

Lay over the whole thickness of the external walls at a minimum height of 150mm above

ground level 20mm thick horizontal damp-proof course in two thicknesses with 75mm

laps.

Lay over the whole of thickness of all internal walls and partitions 13mm horizontal

damp-proof course with 75mm laps.

A. Vertical damp-proof course

Where required because of differences in ground and floor levels, lay on all external walls

a 13mm minimum thickness vertical damp proof course in two coats and connection to

horizontal damp proof courses by angle fillets.

B. Parapet Walls

(a) Continous with asphalt skirtings lay through the full thickness of all

parapet walls a 13mm horizontal damp-proof course

(b) Lay immediately under copings through full thickness of parapet walls a

13mm horizontal damp proof course.

ROOFING IN ASPHALT

C. Felt underlay

To be black sheathing felt to comply with B.S. 747, Class 4A (i0 (bitumen based

impregnated flax felts)

D. Asphalt

To be mastic asphalt for roofing to comply with B.S. 1162 subsection 1418 (natural rock

aggregate with bitumen) or B.S. 988 (limestone aggregate).

E. Workmanship

The asphalt is to be laid in accordance with C.P. 144. Part 2 (Mastic asphalt).

F. Roof covering generally

(a) (On concrete)

lay over the whole of the roof surfaces. On roof plan asphalt of 20mm

minimum thickness in two coats with 75mm laps on and including an

underlay of sheathing felt and laid to falls provided in the screed.

(b) (On timber)

Lay over the whole of the roof surfaces on roof plan asphalt of 20mm

minimum thickness in two coats with 150mm laps on and including an

underlay of sheathing felt and laid to falls provided by firring.

G. Skirting or upstands

(a) Form a two-coat skirting or upstand at junctions of flat roof with parapet walls,

stacks and other abutments to a minimum height of 150mm above highest part

of roof covering with angle fillet joint to roof covering and splayed at top and

turned in at least 20mm into groove in wall and jointed in cement and sand

1:3 (or connected to damp-proof course in parapet walls).

(b) (On timber)

Generally as on concrete.

Also carry asphalt over free-standing timber splayed fillet at junction with parapet

wall on and including heating felt and expanding metal latching. Dress the flashing

set in the wall down over the skirting.

Form all necessary angles and splays, etc., as the work proceeds.

A. Verges

Cover the verges with asphalt in two coats with rounded angles and angle fillet at junction

with roof covering to a minimum thickness of 20mm and to a minimum depth of

150mm. Include raised water check set in not more than 20mm from edge of roof.

B. Eaves

Finish the edge of asphalt against all eaves gutters with fair rounded edge dressed on

to welted metal flashing.

C. Parapet and Valley gutters

Line the parapet or valley gutters with asphalt 20mm thick in two layers on and including

sheathing felt (and expanded metal if of boarded construction) with angle fillets at

bottom and rounded edge to roof covering. Form skirting to parapet wall.

D. Rainwater outlets

(a) (Internal)

Properly dress asphalt to rainwater outlets, finishing with rounded edge, and dress

into luting flange.

(b) (External)

Carry asphalt through outlets in parapet walls with skirting to both sides

properly dress over welted metal flashing and finish with rounded edge.

PAVING AND FLOORING

E. Asphalt

Mastic asphalt to comply with B.S. 1162, subsection 1410 (natural reck asphalt

aggregate) or B.S. 988 subsection 1076 (limestone aggregate) and/or subsection

1451 (limestone aggregate – coloured finish).

F. Workmanship

The asphalt is to be laid in accordance with C.P. 204, Part 4 “Insitu flooring.

G. Paving and Flooring

Pave the areas on to specified thickness in one layer. Form skirtings against walls to a

height of (100mm) and 20mm thick and turn into chase in walling (or finish with

rounded top edge). Include angle fillets at internal angles of skirtings and between

skirting and paving and rounded external angles.

Lay external pavings to falls provided in the concrete towards channels and/or

outlets and the line channels with asphalt 20mm thick.

ROOFING

A. GENERALLY

All roof materials shall be as specified in the Bills of Quantities and laid in accordance

with the manufacturer’s instructions.

GALVANISED MILD STEEL ROOFING

B. Sheeting

Sheeting shall be hot-dip galvanised best quality mild steel sheeting to specified

gauge to comply with B.S. 3083.

C. Laps

Sheeting shall be laid with end laps to comply with C.P. 143201 and side laps of 1½

corrugation on the side away from prevailing winds.

D. Fixing to Timber

The sheets shall be fixed to timber with 6mm diameter galvanised mild steel roof screws

65mm long, each with one plastic “Selawasher” or a Bituminous washer with one

galvanised steel diamond shaped washer.

E. Holes

Holes for bolts or screws shall be punched from the inside of the sheet and through the

ridges of corrugations not the valleys.

F. Ridges and valleys etc

The ridges and valleys etc., shall be formed of galvanised mild steel sheeting of a quality

equal to that of the roofing sheets. Ridges shall be seam bolted to the sheeting on each

side at 450mm centres maximum with 12mm diameter seam bolts 20mm long each with

one plastic washer or a bituminous diamond shaped washer with galvanised

diamond shaped steel washer and one galvanised steel nut. Ridges and valleys shall be

not less than 380mm girth.

G. Bolts and Screws

All fixing bolts and screws shall comply with B.S. 1494.

H. Square Abutments

At square abutments the last two corrugations of the corrugated iron sheets next to

walls shall be flattened and turned up against wall and covered with 18 gauge

galvanised sheet iron apron flashing.

ASBESTOS SHEET ROOFING

A. Sheeting

Asbestos cement roof sheeting and accessories shall be of “Superseven” or other specified

type to comply with B.S. 690 and of an approved colour as stated, shall be simbarits

Brand Manufactured by Kenya Asbestos Cement Co. Ltd., Mombasa unless

otherwise specified. The thickness of the sheeting shall be not less than 6mm or as

specified and shall be laid and fixed strictly in accordance with the manufacturer’s printed

instructions.

The pitches of 15 degrees and under and in exposed position sheets are to be fixed to

every purlin and at every fourth corrugation. At bottom edges the sheeting shall be

fixed every alternate corrugation.

B. Laps

Sheets shall be laid with the end laps to comply with C.P. 143201 and side laps of 1½

corrugation on the side away from the prevailing winds.

C. Fixing

The sheets shall be fixed to timber purlins with 7mm galvanised gimlet pointed

screws 115mm long and to steel angle purlins or “Z” section steel purlins with 7mm

diameter galvanised hook bolts and nuts. All screw and bolt fixing shall have

“selawasher” plastic washers.

D. Holes

Holes for bolts shall be drilled through the ridges of the corrugation not the valleys.

E. Bolts and screws

All fixing Bolts and screws and other accessories shall comply with B.S. 1494.

F. Intersections

Where four sheets meet, two sheets shall be cut and mitred for the full length of the end

lap and the full width or the side lap at the appropriate corners to ensure three

thicknesses of sheeting at this point.

G. Ridges, etc.

Ridges and other accessories shall be supplied as shown on the drawing and shall be

fixed to timber and steel purlins as above described.

H. Fixing to Wall Plates

Where sheeting is fixed to wall plates it is to be executed as described above but in

addition special eaves closer pieces are to be provided if beam filling is not required.

APPLIED ROOFING GENERALLY

A. Protection

The Contractor will take all necessary precautions to ensure that no damage is

caused to the roofing after completion of laying, by further building operations,

storage of heavy objects, traffic or any cause whatsoever.

B. Examination on Completion

Before delivering up the works, the Contractor shall examine the roof coverings, clear

away all rubbish, clean out gutters and rain water pipes and leave a sound watertight

finish.

C. Aluminium - alloy sheeting

To be (24, 22) s.w.g. (0.56, 0.71) aluminium-manganese alloy NS3 sheeting, either:

(a) Corrugated or mansard profile to comply with B.S. 2855, or

(b) Troughed profile to comply with B.S. 3428 (type A or B)

Fittings are to be (22, 20) s.w.g. (0.71, 0.91mm) and are to include roll-top or

angular socketted one end ridge members, hip cappings, eaves fillers, plain and

corrugated side-wall flashings, etc.

D. Translucent corrugated plastic sheeting

To be ‘Unilux” or other approved glass fibre reinforced translucent corrugated

plastic sheeting to comply with B.S. 476. The sizes and corrugations of sheets are to

suit main roof sheeting.

E. Fixing sheeting and fittings

Fixing to be by means of 6mm or 8mm diameter galvanised mild steel hook bolts (to steel

purlins) and/or drive screws ( to wood purlins) together with nuts and soft plastic

washers with dome-shaped caps all to comply with B.S. 1494.

The hook bolts and/or drive screws are to be spaced two per sheet per purlin and

holes are to be drilled in the crown of the corrugations for this purpose.

End laps of sheetings to be 150mm and side laps to be 1 1/2 corrugation or otherwise as

instructed by the manufacturer.

Fittings are to be fixed in the same manner as the general sheeting if the joint lies on a

purlin. If the joint does not lie on a purlin seam bolts of the same diameter as the

hook bolts and/or drive screws are to be used together with nuts and plastic washers as

before described. To be spaced two per sheet.

F. Valley gutters

To be (375mm, 450mm, 525mm or larger) heavy, pressed steel valley gutters to

comply with B.S. 1091 (Alternatively, for corrugated asbestos-cement sheet roofs,

asbestos cement valley gutters to B.S. 569 may be specified).

Joints to be bedded in mastic and bolted with countersunk headed galvanised mild steel

screw bolts, with bolt heads set inside gutter. To be fixed by means of heavy

galvanised pressed steel brackets bolted to the lowest purlins and spaced one per

1M. length of gutter.

A. Roof surfaces generally

Provide and lay over the whole areas shown on roof plan, roof sheeting to purlins as

specified.

B. Ridge

Provide and fix ridge capping complete with gable finials all as specified and as the

work proceeds.

C. Eaves

(a) Allow sheets to project at least 600mm at eaves and joint to beam filling in

cement mortar (1:3) to fill underside of corrugations for the entire thickness

of the beam filling.

(b) Provide and fix eaves fillers fixed to both roof sheeting and wall cladding to

provide eaves enclosure as the work proceeds

D. Verges

(a) Allow roof sheeting to overlap gable walls 75mm minimum and bed point

sheeting to wall in cement mortar (1:3) as the work proceeds.

(b) (To similar sheet gable cladding). Provide verge trims as specified and fix

to roof sheeting only to overlap gable cladding. Make good to gable finial

and ridge capping and at eaves.

E. Valleys

Provide and fix valley gutter as specified between adjacent roof slopes and to falls to

discharge into rainwater heads.

F. Roof lights

In the positions indicated on the roof plan, provide and fix single sheeting as

specified in place of the general roof sheeting to form roof lights.

G. Clay tiles

Shall be as manufactured by Clayworks Ltd., P.O Box 45154, Nairobi or other equal and

approved manufacturer, and shall be true to dimensions as specified.

H. Interlocking concrete tiles

Shall be concrete interlocking tiles as manufactured by Mareba Enterprises Ltd., P.O.

Box 40619, Nairobi or other equal and approved.

The bottom course shall be laid first. Adjustments of the head lap shall be made on at

least first three courses if the rafter length does not accommodate an exact number of

full tiles.

Tiles shall be laid to a minimum head lap of 76mm side lap of 35mm. The maximum

batten gauge shall be 343mm.

Shingles

A. Battens

To be pressure impregnated, 50 x 25mm sawn softwood battens set to 125mm

gauge.

B. Shingles

To be first grade, pressure impregnated, or oil dipped edge grain (i.e. cut from the

block at right angles to the annular rings), sawn cedar shingles average size 500 x

200mm and tapering from 3mm thick at the head to 10mm thick at the tail.

C Laying Shingles

To be laid breaking joint and nailed through two thicknesses of shingles to each

batten. To have double course (full length) at eaves and one-and-a-half width

shingles in each alternate course at verges to break joint. Ridges and hips to be

capped with shingles as main roof.

D. Roofing surfaces generally

Form ridges hips and finish edges at eaves and verges, all as specified, and cut and fit

shingles at abutments and valleys to receive metal flashings.

Bituminous Felt Roofing

E. Generally

All bituminous felt as to be manufactured and applied strictly in accordance with

appropriate B.S. or C.P. as stated hereafter.

F. Bituminous Roofing Felt

To be built-up bituminous felt roofing in three layers of self finished bitumen felt

weighing 13.6kg/10m2 to comply with B.S. 747, Class 1C (i.e. fibre based).

G. Insulation and vapour barrier

To be 13mm thick approved fiberboard insulation laid with butt joints to a vapour

barrier consisting of one layer of coated bitumen roofing felt weighing not less that

13.6kg/m2 laid over the whole surface.

H. Surface finish (non-pedestrian traffic)

To be grey stone (or white marble) chippings, average size 12mm laid over the

surface in hot bitumen dressing compound. Chippings to be omitted in gutters and

stopped short of edges and 300mm clear of rainwater outlets and the bottom of angle

fillets.

Roofs steeper than 10 degrees are not to have chippings.

The areas not covered with chippings shall be finished with a layer of mineral

surfaced, bitumen felt weighing 36kg/m2 instead of the top layer of roofing.

A. Surface finish (pedestrian traffic)

To be fine bitumen macadam lightly rolled to 13mm thickness and sprinkled with

3mm limestone grit rolled in.

B. Roofing generally

To be laid in three layers as specified with 50mm side laps and 75mm end laps,

staggered, the layers bonded together with hot bitumen bending compound as

described in C.P. 144.

C. Abutments

Felt to be carried up abutment over fillet (concrete or wood) and each layer tapered to a

height of 150mm above roof surface as skirting to be covered by metal flashing.

D. Verges

Felt to be carried over roll (concrete or wood) and over verge to a depth of 150mm and

bonded to edges of verge with hot bitumen bonding compound.

E. Parapet gutters

Felt to be carried into gutter and up parapet wall as abutment. Felt to be laid to lap

with, and not against, the fall in the gutter.

F. Eaves gutter

Felt to be laid over edge of roof and dressed into gutter with edge welted.

G. Rainwater outlets

Felt to be carried through outlets in parapet walls with skirtings to both sides of

outlets and dressed over edge of parapet wall and into rainwater head.

H. Roof surfaces generally

Provide and fix insulation and vapour barrier, lay surface dressing and form junction and

joints at abutments, verges, eaves and parapet gutters and rainwater outlets, all as

previously specified.

I. SAMPLES

The Contractor shall as and when required by the Architect, submit and deliver

samples of any materials for testing.

J. STATEMENT AS TO SCREED AND UNDERBED

The Contractor is to obtain from Sub-Contractor a statement in writing to the effect that

the screed and/or underbed is laid to the correct falls and is clean and otherwise

satisfactory before the covering of felt is laid. A copy of the statement is to be

forwarded to the Architect.

A. GUARANTEE

The Contractor is to obtain from the specialist firm a written guarantee and

undertaking to the effect that during a period of two years from and after the

certified date of completion of the works, such sub-Contractor shall at his own

expense make good to the satisfaction of the Architect, all and any defects in the felt

roofing work which shall be attributable to improper materials or faulty

workmanship and shall bear the cost of any consequential damage as is provided for

in such guarantee.

MATERIALS

B. PRIMER AND BONDING COMPOUND

Primer and bonding compound shall be oxidised or ‘blown’ bitumen melted and

applied hot.

WORKMANSHIP

C. PREPARATION

All surfaces to receive felt are to be cleaned before and as work proceed. Felt shall not

be laid until sufficient time has been allowed for the screed and underbed to

become completely dry and free from water vapour. Felt shall not be laid whilst the

screed or underbed is wet.

D. FALLS

All work shall be laid to falls without hollows or loose patches.

E. PRIMING

Primer shall be applied overall to vertical surfaces, kerbs and skirtings.

F. LAPS, BONDING, ETC.

All roofing shall be laid with number of layers of felt described to a maximum

thickness of 10mm lapped across falls with minimum laps of 50mm at edges and

75mm at ends of sheets, fully hot bonded either by pouring and rolling or mopping

with bitumen bonding compound laid to an even thickness using 13kg bitumen per

square metre of roofing between layers, with successive layers of felt laid breaking

joint.

G. STAINS, ETC.

All adjoining work shall be protected from damage during laying and all stains shall be

removed and made good.

CARPENTRY AND JOINERY

MATERIALS

A. QUALITIES AND GRADES OF TIMBER

(i) All timber used for permanent work in the building shall conform in all

respects to K.S. 02-17.

(ii) The qualities and grades of timber stated hereinafter conform to Table 1 of

Section 4 of K.S. 02-17 which is reproduced hereunder.

GRADE APPLICATION

F Furniture and high class joinery

S75 Structural grade having grade stress

value of 75% of basic stress

S50 Structural grade having grade stress

value of 50% of basic stress

C General construction grade for non-

stressed construction

GJ General Joinery

(iii) All timber for permanent work in the building shall before use be approved

by th eArchitect for quality in accordance with the foregoing specification

for its respective grade. Any timber not so approved by the Architect shall

be removed from the Site forthwith.

B. INSECT DAMAGE

All timbers whether graded or ungraded, and including shuttering scaffolding and the

like shall be free of live borer, beetle or other insect attack when brought upon the

site.

The Contractor shall be responsible up to the end of the maintenance period for

executing at his own cost all work necessary to eradicate insect attack of timber

which becomes evident including the replacement of timbers attacked or suspected

of being attacked, notwithstanding that the timber concerned may have been

inspected and passed as fit for use.

C. SEASONING OF TIMBER

All carpentry timbers are to be seasoned to an average moisture content of not more than

20%. The Contractor is to make available on site a meter for testing moisture

content of all timber delivered.

A. PREPARATION AND PROTECTION OF TIMBER

(i) All timber necessary for the works is to be purchased immediately and

when delivered, is to be openstacked for such further seasoning as may be

necessary. Preparation of timber is to be commenced as early as possible.

(ii) All timber and assembled woodwork is to be protected from the weather

and stored in such a way as to prevent attack by decay, fungi, termites or

other insects.

B. SPECIES OF TIMBER

Only those timbers specified in these Bills of Quantities are to be used for the

Works, unless alternatives are authorised by the Architect in writing.

C. PRESSURE IMPREGNATED TIMBER

(i) All timber described as pressure impregnated shall be impregnated under

vacuum and pressure with the “Celcure” wood preservative with an average

absorption of not less that 6.7kgs. of dry Celcure salt per cubic metre. In

case of resistant species where this retention cannot be obtained the timber

shall be treated to refusal point. All treated timber shall be exposed to wet

conditions for at least 14 days after treatment has been carried out. All cut

ends, drilling or fabrications on the Site producing new surface shall be

thoroughly brushed or soaked with “Celcure” salts applied in accordance

with the manufacturer’s instructions.

(ii) Any other method of timber impregnation will only be allowed at the

Architect’s approval.

D. TIMBER BUILT INTO MASONRY

Ends of timber built into walls shall be thoroughly brush treated with creosote or

other approved preservative and clear space maintained around timbers where they

adjoin the walls.

E. DIMENSIONS

Before putting in hand any joinery work, whether built-in or fixed later, the joiner is to

ascertain and check on site all dimensions, which affect or govern the joinery

work.

F. BLOCKBOARD

Blockboard shall be of approved local or imported manufacture, to B.S. 3444, glued

throughout and softwood or hardwood faced as hereinafter specified and equal to a

sample to be deposited with the Architect for approval and which when so approved

shall form the standard for the works.

G. PLYWOOD

Plywood to be of approved manufacture according in all respects with B.S. 1455;

interior type to be Grade I and exterior type Grade II weather-resistant (not less than

B.R. Bonding).

A. FIBREBOARD

Shall be insulating board to comply with B.S. 1142 of the types specified and of

approved manufacture.

B. TEMPERED HARDWOOD

To be of approved manufacture in accordance with B.S. 1142, suitable for painting,

prepared and fixed in accordance with the maker’s instruction.

C. ASBESTOS SHEETING

To be “Simbarite” flat sheets of 4mm or 6mm as described hereafter.

D. LAMINATED PLASTIC

To be 1.6mm Formica or other equal and approved laminated plastic sheet to B.S.

3794 in colours to be selected by the Architect and bonded on with the

manufacturer’s recommended adhesive all in accordance with their printed

instructions.

E. WOOD PARAQUET FLOORS

(i) To be to specified thickness and not less than 8mm parquet tiles supplied

and laid by a Specialist all to the approval of the Architect. The screed is

to be primed and when cured the tiles are to be bedded thereon in adhesive;

both the primer and adhesive are to be recommended and approved by the

tile supplier.

(ii) Upon completion and immediately prior to applying the sealer, the surface

is to be twice machine sanded using first coarse and then fine sand paper

and brushed perfectly clean.

F. MAKUTI

To be first quality and obtained from a source approved by the Architect and each piece

to be fixed to roof timbers securely tying on with sisal string.

G. FLUSH DOOR

Shall comply in all respects other than the following modifications with

B.S. 459 part 2:-

(a) To be 45mm thick and of the size stated in the Bills of Quantities.

(b) Core shall be seasoned softwood grade GJ.

(c) Hardwood lipping to be Graded thick tongued on back face into styles and rails

of core mitred at angles and glued in.

(d) Semi-Solid Core to consist of 75mm wide style, top and bottom rails all

framed together with two 500mm x 150mm look blocks framed in and

20mm intermediate horizontal rails at 50mm centres stub tenoned in each

end to styles. Each horizontal rail and top and bottom lipping to have

12mm diameter hole bored through to ensure air circulation through core.

Plywood facing to be 4mm thick.

(e) Solid Core (and half-hour type fire check doors) to consist of 75mm styles top

and bottom rails with solid core of 12mm horizontal strips glued together

under pressure. The strips to be put together with the grain alternating and to be

tongued on edge and let into vertical grooves in styles. Plywood facing to be

6mm thick.

(f) A sample must be approved by the Architect before an order is placed and all

doors must be equal to the standard of the approved sample.

A. NAILS, SPIKES AND BOLTS

Nails, spikes and bolts shall be the best quality mild steel and of lengths and weights

approved by the Architect. Nails shall comply with B.S. 1202, wood screws with

B.S. 1210, and bolts with B.S. 916.

WORKMANSHIP

B. JOINTING

(i) All joints must be made as specified or detailed and the execution of all

jointing shall be to the satisfaction of the Architect.

(ii) Jointing surfaces of all connections exposed to the weather are to be thickly

primed except where glueing is specified. Surfaces are to be in good

contact over the whole area of the joint before fastings are applied.

(iii) No nails, screws or bolts are to bolts are to be placed in any end split. If

splitting is likely or is encountered in the course of the work, holes for nails

are to be pre-bored at diameters not exceeding 4/5ths of the diameter of the

nails. Clenched nails must be bent at right angles to the grain. Lead holes

are to be bored for all screws.

(iv) Where the use of bolts and washers is specified the holes are to be bored

from both sides of the timber and to be a diameter D + D/16 where D is the

diameter of the bolts. Nuts must be brought up tight but care is to be taken

to avoid crushing of the timber under the washers.

(v) Joints in joinery must be as specified or detailed and so designed and

secured so to resist or compensate for any stresses to which they may be

subjected. All nails, springs, etc., are to be punched and puttied.

(vi) Loose joints are to be made where provision must be made for shrinkage,

glued joints where shrinking need not be considered and where sealed

joints are required. All glued joints shall be crosstongued or otherwise

reinforced.

(vii) Glues for load-bearing joints or where conditions may be damp must be of

the resin type. For non-load-bearing joints, or where dry conditions can be

guaranteed, resin or organic glues may be used.

C. FRAMES WORK

The word framed shall mean and include all the best known methods of jointing

woodwork together by mortice, tenon, dovetail or other methods, and for forming all

necessary stops, mitres or mason’s mitres in members which are moulded, rebated,

etc.

A. PLUGGING

Plugging and fixing to walls in all trades shall be executed by “Rawlplugging” or

similar approved proprietary methods all in accordance with the manufacturer’s

printed directions. Hacking of holes and filling with timber plugs will not be

permitted under any circumstances.

B. CARPENTRY

(i) All carpentry shall be executed with workmanship of the best quality.

Scantlings and boards shall be accurately sawn and shall be uniform in

width and thickness throughout and shall be as long as possible and

practicable in order to eliminate joints.

(ii) All work shall be left with a sawn surface except where specified to be

wrot.

(iii) All work shall be accurately set out and in strict accordance with the

drawings, and shall be framed together and securely fixed in the best

possible manner with properly made joints. Provide all brads, nails,

screws, etc., as necessary and as directed and approved.

(iv) Actual dimensions of scantlings for carpentry shall not vary from specified

dimensions by more than +3mm – 1.5mm. Sizes and thicknesses of wrot

carpentry timbers are nominal, that is to say a variation of 3mm from the

specified sizes will be allowed from each wrot surface unless the thickness

or size is described as “finished” in which case no variation from the stated

thickness or size will be permitted.

JOINERY

C. GENERALLY

All joinery work shall be wrot unless otherwise described.

(i) Sizes and thickness of joinery are nominal that is to say a variation of 3mm

from the specified sizes will be allowed from each wrot surface unless the

thickness or size is described as “finished” in which case no variation from

the stated thickness or size will be permitted.

(ii) No joinery to be put in hand until the details have been supplied or

approved by the Architect and in all cases the details are to be worked to.

(iii) All joinery shall be executed with workmanship of the best quality in strict

accordance with the detailed drawings, mouldings shall be accurately and

truly run on the solid and all work planed, sand-papered and finished to the

approval of the Architect.

All arrises to be slightly rounded. All framed work shall be cut out, and

framed together as soon after the commencement of the building as is

practicable but should not be wedged up until the building is ready for

fixing the same and any portions that warp, get in winding, develop shakes

or other defects shall be replaced with new. In doors frames, etc., the heart

face of the timber shall be fixed away from the wall. As soon as required

for fixing in the building the framing shall be glued together with glue as

described and properly edged to pinned, etc., as directed.

(iv) All bends, fillets and small members shall be fixed with round or oval

brads or nails well punched in and stopped. All larger members shall be

fixed with screws, the screws let in and pelleted over with wood pellets to

match the grain.

(v) Cups and screws for fixing beads and fillets shall be spaced 150mm apart

and 25mm from angles.

(vi) All joinery immediately upon delivery to the site is to be stored and

protected from the weather.

(vii) All joinery is to be primed before fixing but no work is to be primed until it

has been approved by the Architect.

(viii) All fixed joinery, which is liable to become bruised or damaged in any way,

shall be properly cased and protected by the Contractor until the completion

of the Works.

(ix) When natural finish is specified, the timber in adjacent pieces shall be

matched and uniform or symmetrical in colour and grain.

A. SEASONING OF TIMBER

All joinery timbers are to be seasoned to an average moisture content of not more that

15%. The Contractor is to make available on site a meter for testing moisture content of

all timber delivered.

B. PREPARATION AND PROTECTION OF TIMBER

(i) All timber necessary for the Works is to be purchased immediately and

when delivered is to be openstacked for such further seasoning as may be

necessary. Preparation of the timber is to be commenced as early as

possible.

(ii) All timber and assembled woodwork is to be protected from the weather

and stored in such a way as to prevent attack by decay, fungi termites or

other insects.

C. SPECIES OF TIMBER

Only those timbers specified in these Bills of Quantities are to be used for the

Works, unless alternatives are authorised by the Architect in writing.

D. PRESSURE IMPREGNATED TIMBER

(i) All timber described as pressure impregnated shall be impregnated under

vacuum and pressure with ‘Celcure” wood preservative with an average

absorption of not less than 6.7kgs of dry Celcure salt per cubic metre. In

case of resistant species where this retention cannot be obtained the timber

shall be treated to refusal point. All treated timber shall be exposed to wet

conditions for at least 14 days after treatment has been carried out. All cut

ends, drilling or fabrications on the Site producing new surface shall be

thoroughly brushed or soaked with “Celcure B” salts applied in accordance

with the manufacture’s instructions.

(ii) Any other method of timber impregnation will only be allowed at the

Architect’s approval.

A. TIMBER BUILT INTO MASONRY

Ends of timber built into walls shall be thoroughly brush treated with creosote or

other approved preservative and clear air space maintained around the timber where

they adjoin the walls.

B. DIMENSIONS

Before putting in hand any joinery work, whether built-in or fixed later, the joiner is to

ascertain and check on site all dimensions, which affect or govern the joinery

work.

C. BLOCKBOARD

Blockboard shall be of approved local or imported manufacture, to B.S. 3444, glued

throughout and softwood or hardwood faced as herein after specified and equal to a

sample to be deposited with the Architect for approval and which when so approved

shall form the standard for the Works.

D. GUMPOLES

Shall be to the species eucalyptus saligna or eucalyptus maisenii, shall be of the

minimum diameters stated and shall be stripped of bark before incorporation in the

works.

The Contractors attention is drawn to the length of the poles, each of which must be in a

single length; splicing will not be allowed.

E. PRICING NOTES

Prices for joinery work shall include for slightly rounding all arrises of timber

members.

Prices for hanging doors must include for any type either folding, swinging or

sliding.

Prices shall also include for all necessary glueing, spiking, nailing, and screwing

whether specification mentioned or not.

Prices for items described as plugged shall include for fixing with screws.

IRONMONGERY

F. IRONMONGERY GENERALLY

(i) Ironmongery shall be fixed with suitable screws to match and prices shall

include for this.

(ii) All locks and ironmongery shall be fixed before the woodwork is painted,

handles shall be removed before the painting commences, carefully stored

and refixed after completion of painting.

(iii) All locks, springs and other items of ironmongery with movable parts shall

be properly tested, cleaned and adjusted where necessary to ensure proper

working order at the completion of the works and left in perfect working

order by the Contractor.

(iv) The keys of all locks shall have labels attached with door references

marked on before handing to the Architect.

A. PRICING NOTES

Prices for fixing ironmongery shall include for fixing before woodwork is decorated and

for removing lock handles, finger plates and the like and re-fixing and oiling after

decorating is completed.

METALWORK

B. MATERIALS GENERALLY

All materials shall be the best of their respective kinds, free from defects and all

works is to be carried out in the most workmanlike manner and strictly as directed

by the Architect. The materials in all stages of transportation, handling and

stacking shall be kept clean and protected from injury by breaking, bending or

distortion and weather action.

C. MILD STEEL

Mild steel shall comply with KS. 02-18 and B.S. 15.

D. BOLTS, NUTS AND WASHERS

These shall be fabricated from materials which comply with K.S. 02-18 and B.S. 15, and

each manufactured item shall comply with the appropriate standard.

E. TUBULAR RAILS, ETC.

Shall be galvanised mild steel “medium” duty to B.S. 1387.

F. HOLLOW SECTION TUBING

Square and rectangular hollow section tubing shall be hot rolled mild steel in

accordance with Grade 43 C of B.S. 4360.

G. FABRICATED WORK

All screwed work shall have full threads conforming to B.S. 21. Welded work is to

comply with the provisions of B.S. 538 and shall be carried out so that no distortion

to the members occurs and upon.

H. GALVANISED SHEET STEEL

To be the thickness specified and of approved manufacture to K.S. 06-02 best

quality mild steel sheets cold rolled close annealed patent flattened and hot dip

galvanised.

I. ALUMINIUM

Wrought aluminium shall be of the alloys described and shall comply with B.S. 1474 –

extruded round tube and hollow sections B.S. 1476 – extruded tube and hollow sections

B.S. 1476 extruded bars, rods and sections B.S. 1477 – plate.

A. SMITHING ETC.

All smithing and bending shall be soundly and neatly executed, care being taken not

to overheat.

B. FORGING

All straps, bolts and similar work shall be forged neat and clean from the anvil.

C. WELDING

All welding shall be neatly and cleanly executed and no excess weld metal at joints

will be accepted. All welds are to be ground smooth on completion and prices are to

include for this.

D. WORKMANSHIP

All structural steel work is to be erected in accordance with B.S. 449. “The use

of structural steel in Buildings”.

PLUMBING INSTALLATIONS

E. QUALIFICATIONS OF THE RULES OF THE S.M.M.

Jointing Pipes

(i) Notwithstanding the provisions of S.M.M. Clause Q.9 (b), the prices for all

galvanised steel screwed pipes shall be deemed to include for jointing with

hemp and red lead or “Boss white unless otherwise described and the prices

for all cast iron pipes shall be deemed to include for jointing with a gasket

of hemp and cold caulking compound unless otherwise described.

Provision of Holes

(ii) Notwithstanding the provisions of S.M.M. Clause Q.1 (g), the provision

of holes shall be deemed to be included in the description of fixing.

F. DEFINITIONS

(i) Painting

The preparation of surfaces shall be deemed to be included with the

description for painting. Specific requirements relating to the preparation of

surfaces are given in the WORKMANSHIP section of these preambles. In

the absence of specific requirement surfaces shall be prepared in the

manner recommended by the manufacturer of the paint being used.

(ii) Welding

In the absence of specific requirements the techniques and materials

employed in welding shall be selected with due regard to the character of the

work and the metals being connected.

(iii) Background reuiring plugging

The term ‘backgrounds requiring plugging’ shall mean any or all of the

backgrounds described in S.M.M. Clause Q.1 (h) (iv), and shall be deemed to

include the associated plugging.

(iv) Plugging

The term ‘plugging’ shall mean provision and fixing of hardwood or

approved proprietory plugs, or, at the Contractor’s option, fixing by

means of a cartridge operated rivet gun or other approved mechanical

means.

(v) Surface finishes

In the absence of specific requirements, the treatment and finish of pipe

fittings shall be appropriate to the finish of the pipes with which they are

associated.

(vi) Pipes sizes

The size of the pipe shall be the diameter of the bore.

A. GENERALLY

Execution of plumbing works

All plumbing work shall be executed in accordance with the best principles of

modern practice by a firm of fully qualified and registered plumbers. The

Contractor shall obtain the Architects written approval to the firm he proposes to

employ before the plumbing works are commenced.

The Contractor shall obtain the Architects prior written approval to the position of all

pipe runs, valve positions, control points, access points and the like for all plumbing

installations.

At the time of practical completion the Contractor shall prepare and hand to the

Architect four copies of plans and diagrams showing the positions of all pipe runs,

valve position, control points, access points and the like for all plumbing

installations. Such plans and diagrams shall be to the Architects approval, and

practical completion of the plumbing installation shall be deemed to have taken

place only after receipt by the Architect of such approved plans and diagrams.

All plumbing and drainage works shall be executed in accordance with the Regulations

of the Local Authorities. The Contractor shall give all notices and pay all fees

required thereunder. The amount of such fees shall be deemed to be included in

the Contract Sum, unless they are expressly included in these documents by way of a

Provisional Sum or Prime Cost Sum.

B. RAINWATER INSTALLATIONS

Plastic pipes

Plastic pipes, fittings and accessories shall comply with B.S. 4576 heavy grade PVC,

colour to be selected by the Architect: fixed true to line with straps supplied by the

manufacturer screwed to hardwood plugs with galvanised screws, and jointed all in

accordance with manufacturer’s instructions. Rubber sealing rings shall comply

with B.S. 2494 Part 2.

Fixing

Except where adequately restrained and supported by being built in, all pipes and

fittings shall be with one holderbat to each socket. Pipes less than 75mm diameter

shall be fixed 25mm clear of walls and those 75mm diameter and over 40mm clear

of walls. Holderbats shall comply with BS 416, Table 21 coated.

A. ASBESTOS CEMENT PIPES

Asbestos cement pipes are to be B.S. 582 with joints made in tarred hemp and 25mm

bituminous compound caulked in with slightly moistened neat cement.

Pipes are to be fixed clear of walls with approved bitumen dipped pipe clips.

B. GALVANISED STEEL TUBES AND FITTINGS

Galvanised steel tubing shall comply with B.S. 1387 with galvanised reinforced

malleable cast iron fittings complying with B.S. 143 and 1256 with B.S. 1256

threads.

Jointing – Tubing and fittings shall be seam-jointed using hemp and red lead putty of

‘Boss’ white.

Fixing – Tubes shall be fixed clear of walls or soffits, with galvanised malleable iron

brackets complying with B.S. 1494, Part 3 (or with hangers or special fixing where

so described), spaced at not more than 3 metres centres.

C. PITCH-IMPREGNATED FIBRE DRAIN PIPE, COUPLINGS AND FITTINGS

Pitch fibre drain pipes etc. shall be to B.S. 2760 and of approved manufacture.

Joints shall be made with straight couplings as indicated in the B.S. and the laying,

cutting and jointing shall be executed strictly in

accordance with the manufacture’s instructions.

Joints generally

All joints shall be perfectly smooth inside without excrescences.

Sleeves

All drains passing through walls or foundations shall have sleeves of cast

iron pipe of sufficient size to allow a 3mm clearance round the drain.

D. BRACKETS AND HANGERS

Brackets for supporting horizontal drains from walls or beams, shall be of

75mm x 75mm x 10mm coated steel tee with one end rounded up and of

sufficient length for the other end to be built in for a depth of 225mm.

Hangers for suspending drains from soffits shall consist of a pair of forged

50mm x 10mm coated steel half pipe saddles bolted together around the

one end forged into an eye to receive the bolt. The top of the bar shall

either be fanged for casting in, or shall be threaded with nut and plate

washer. Where fixed through floors the projecting end of the bar shall be

cut off flush with the nut.

A. WIRE BALLONS

Wire balloons shall be copper; mosquito proofed and shall comply with B.S.

416 table 22.

B. SANITARY FITTINGS

Sanitary Fittings shall be as specified. In the event that the appliances specified are

unavailable, the supply of alternatives which are at least equal in every respect in

of the Architect.

C. WORKMANSHIP

Any bead or feather formed when the pipe is cut, which reduces the internal

diameter of the pipe must be removed before the pipe is jointed.

Bends on copper or wrought iron pipes shall be formed on approved machine and in no

case to an internal radius of less than eight time the outside diameter of the pipe.

In no circumstances will the contractor be allowed to use elbows on pipes of 30mm

diameter and above.

All tubing exposed on faces of walls shall be fixed at least 25mm clear of adjacent

surfaces with approved holderbats built into walls not more than 2.0m apart and not

more than 1.0m for PVC tubing.

Pipes fixed in roof spaces or joinery shall be fixed with approved clips screwed to

timber members not more than 2.0m apart.

Easy bends on the line of piping shall be made with an approved bending machine; no

firebends will be permitted. Where elbows are required they shall be of round

pattern.

D. PIPE FIXED IN WALL CHASES

Where directed, pipes shall be fixed in chases in walling and secured with approved

holderbats built into walls not more that 2.0m apart.

E. FIXING TO WALLS

All surface fixings unless otherwise specified shall be carried out with “PHILPLUG”

or “Rawlplugs”.

The fixing holes shall be drilled with special mansory drill and not cut with a chisel

under no circumstances will the use of wooden plugs be permitted.

The Contractor shall include for making good all walling and surface finishes.

F. WASTES

Wastes are to be provided as directed by the Architect. Unless otherwise specified or

shown on the drawing sink, shower and bath wastes are to be of 38mm tubing and

lavatory basins of 32mm tubing.

The wastes shall be set to fall through an external wall and shall be jointed to a back inlet

gulley or have splay cut end set or discharge over a gulley.

A. TRAPS

Unless otherwise specified traps shall be brass to comply with B.S. 1184 and shall be

provided with screwed cleaning eyes.

Where “antvac” traps are specified or shown on the drawings, they are to be

“Grevac Senior” or other approved patent trap.

B. SOIL AND VENTILATING PIPES

Soil and ventilating pipes shall be 100mm diameter cast iron or UPV pipe as before

described and shall be provided in the positions specified or shown on the drawings

at the head of each main drain.

The top of the pipe shall be provided with an approved galvanised wire balloon

grating on UPVC vent cowl and shall finish at least 450mm above eaves or flat roof

level.

C. TESTING

The Contractor shall from time to time as required to suit the progress of the

building, air-test the plumbing and internal drainage in sections to the satisfaction

of the Architect, before any such work is covered. At the completion of the works

all soil pipes and branches and waste pipes and other parts of the internal drainage

works connected directly with any sewerage drain or sewerage drain ventilating pipe

or soil pipes, shall be subjected to a water test and be proved capable of resisting a

pressure of 1.5 metres head of water and the Architect may also direct that a sample

or any other test be applied to any other part of the drainage or ventilating system as

he thinks desirable. Everything necessary for these tests shall be supplied by the

Contractor.

D. CLEANSING

On completion of the works, immediately before handing over, the Contractor shall

cleanse thoroughly the whole of the system and prove that it is functioning freely to

the satisfaction of the Architect.

E. HABITATION CERTIFICATE

On completion, the Contractor shall obtain a ‘Habitation Certificate form the Local

Council and forward to the Architect.

F. HOT AND COLD WATER INSTALLATIONS

Galvanised steel tubes and fittings

Galvanised steel tubes shall comply with B.S. 1387 heavy grade for rising mains and

branches off rising mains, and medium grade for distributing pipes; except where the

latter are in contact with the ground when they shall be heavy grade. Fittings shall

be galvanised reinforced malleable cast iron fittings complying with B.S. 143 and

1256 with B.S. 1256 threads.

Jointing – Tubes and fittings shall be screw-jointed using hemp and red lead putty of

‘Boss’ white. Connections to flushing cisterns, bib taps and the like, shall be made

with copper or other equal and approved connectors to facilitate removal.

Fixing – Unless described as being fixed in chases, tubes shall be fixed clear of walls

and soffits with galvanised malleable iron brackets complying with B.S. 1494, Part

3 (or with hangers or special fixing where so described), spaced at not more than the

distance in the following tables.

SPACING OF FIXINGS

Size of pipe Maximum spacing in metres

13mm 2.00

19mm 2.50

25mm to 50mm 3.00

Over 50mm 3.50

A. PIPEWORK GENERALLY

Pipes shall be in the maximum lengths possible to avoid unnecessary jointing.

Pipes shall be fixed to sufficient falls to prevent air locks and to enable the

systems to be drained.

B. LEEVES

Where sleeves are required for pipes passing through concrete, or blockwork, they shall

be of galvanised steel tube of sufficient diameter to give at least 3mm clearance

around the pipe.

C. BRASSWORK

Drainage taps with loose keys shall comply with B.S. 2879 type B.

Ball valves - shall be ‘Portsmouth’ type complying with B.S. 1212 for high or low

pressure as described fitted with a silencer tube drilled with a 6mm hole above the

level of the overflow warning pipe. Floats not exceeding 150mm diameter shall be

plastic type complying with B.S. 2456; larger floats shall be copper type complying

with B.S. 1968, Class C. Bib taps shall comply with B.S. 1010 and shall be of brass

with fixed jumpers and where so described shall be chromium plated or shall have

nozzle screwed for hose union and locking arm.

Stop valves shall comply with B.S. 1010 and shall be of brass with crutch handles or

loose key where so described. Those in exposed positions shall have polished brass

bodies.

Sluice valves shall comply with B.S. 1218, Class 1 or as described.

Gate valves shall comply with B.S. 1952 Class 150 solid or split wedge and non-

rising stem.

D. TANKS AND CISTERNS

Store tanks shall be sectional pressed galvanised steel tanks of 4.5mm plate of

approved manufacture complete with cover inspection manhole. Tanks shall be

assembled entirely in accordance with the manufacturer’s written instructions.

Storage cisterns shall comply with B.S. 417, Grade A, galvanised with one piece

galvanised covers and shall be of the sizes specified or shown on the drawings

supplied with removable sheet iron covers with edges turned down 25mm to suit

exact size of tank.

Tanks shall have an overflow pipe of greater diameter than the incoming service

and shall be set to discharge 300mm beyond the external wall of the building.

The end of the pipe shall be splay cut and have galvanised mosquito proof coffee

gauze soldered on.

A. HOT WATER CYLINDERS

Hot water cylinders are to be manufactured locally from No. 12 gauge welded

mild steel, galvanised after manufacture, with domed top, feed connection and

immersion heater bosses.

The cylinder is to be lagged with approved diatomite and asbestos fibre

composition having a tested minimum insulating value of 0.60 grm calories heat

loss per second per square centimeter per degree centigrade at 100 degrees

centigrade, mixed and applied in accordance with the manufacturer’s

instructions, reinforced with small mesh chicken wire.

B. TESTING

Clean out storage cisterns and tanks, including removal of all swarf, fill and

test the whole of the hot and cold water installations, rectify all defects,

drain and leave in a clean, serviceable condition.

C. FIRE MAIN INSTALLATION - DRY RISING MAINS

Fire brigade

All work shall be to the satisfaction of the Local Fire Brigade.

Approval of fittings

All inlets, outlets, valves and other fittings shall be of a pattern approved by the

local water undertaking and where they so require, shall bear their stamp of

approval.

D. GALVANISED STEEL TUBE AND FITTINGS

Galvanised steel tubing for dry rising mains shall comply with B.S. 1387, heavy

grade, screwed and socketted, with galvanised malleable cast iron fittings

complying with B.S. 1256.

All changes f directions in the run of piping shall be made with standard bends,

springs or long turn fittings, elbows shall not be used. Tubing and fittings shall be

jointed with hemp and red lead putty of ‘Boss’ white.

E. INLET BOXES

Inlet boxes shall comply with B.S. 3980 rust proofed steel, except that the open

panel of the door shall not be glazed but shall be filled with a laminated reinforced

glass fibre panel as listed with the words ‘DRY RISER INLET’ bonded between

laminates.

A INLET BREECHINGS

Inlet breechings shall be constructed in gunmetal, flanged for attachment to the riser

and fitted with two inlets, each consisting of a 63mm instantaneous male coupling

conforming to B.S. 336 and a back pressure valve and removable blank cap secured

to the valve with a length of chain. The breeching shall be fitted with a 25mm drain

valve with black capped hose union.

B. OUTLETS

Outlets shall comprise a gate pattern valve constructed in gunmetal, flanged for

attachment to the riser, fitted with a 63mm instantaneous female conforming to B.S.

336 and a removable blank cap secured to the valve with a length of chain. The

valve shall have a clear waterway when open and the valve cover shall be securely

fitted so that it does not unscrew when the valve is operated. The spindle shall be not

less than 22mm diameter and shall have a gunmetal hand wheel approximately

150mm in diameter marked with “OPEN’ and “SHUT” directions. The outlet valve

shall be kept locked shut with a locking strap and padlock.

C. PRECAUTIONS AGAINST THEFT

All bolts and studs used in the assembly of dry rising mains and valves and exposed

to view, are to be spot welded, either on the head or thread.

D. GALVANISED STEEL TUBES AND FITTINGS

Galvanised steel tubes and fittings shall comply with B.S. 1387 with galvanised

reinforced malleable cast iron fittings complying with B.S. 143 and 1256 with B.S.

1256 threads.

Jointing – Tubing and fitting shall be seam-jointed using hemp and red lead putty or

‘Boss’ white.

Fixing – Tubes shall be fixed clear of walls or soffits, with galvanised malleable iron

brackets complying with B.S. 1494 part 3 (or with hangers or special fixing where so

described), spaced at not more than 3 metre centres.

E. RAINWATER OUTLETS

PVC rainwater outlets shall be manufactured to the sizes and profiles measured

herein from heavy grade PVC, with a minimum 75mm wide flange all round the top

for fixing to roof surfaces, fully bedded in hot bitumen and jointed to the PVC

rainwater pipes.

Fulbora type coated cast iron outlets, with grating, hook bolt and clamping device

shall be cast into concrete or built into concrete or built into blockwork in the

positions and to the elevation shown on the drawings, and jointed with caulked lead

to rainwater pipes.

F. TESTING

Rainwater installations shall be subjected to a water test and proved capable of

withstanding a pressure of 1.05m head of water to the satisfaction of the Architect.

Any defects are to be made good by the Contractor and the whole system left sound

and perfect.

A. SANTARY INSTALLATION

Bye-laws

All the work shall comply with the requirements of the Local Authorities bye-laws

and drainage regulations and shall be executed to the satisfaction of the Architect

and the Local Authority.

B. SETTING OUT

The position of all pipes runs, including joints and connections, holes and the like, shall

be agreed with the Architect before work is commenced.

C. POLYTHENE TUBING

The polythene tubing for cold water services shall be normal or heavy gauge as

required or specified to comply with B.S. 1972. Joints and fittings shall be in

accordance with the manufacturer’s printed instructions.

D. SPUN CAST IRON PIPES, CAST IRON FITTINGS AND ACCESSORIES

Spun cast iron pipes and sand cast iron fittings shall comply with B.S. 416

for medium grade coated pipes and fittings. Sockets and spigots shall be type B

on pipes and type A on fittings.

Access doors shall be oval type with asbestos washers and manganese

bronze bolts.

Jointing – pipe and fittings shall be jointed with a gasket of hemp and

tightly caulked cold with caulking compound.

E. TESTING

Dry rising mains shall be hydraulically tested to a pressure of 20Kg/sq. cm.

PAVINGS AND PLASTER WORK

F. QUALIFICATIONS TO THE RULES OF THE S.M.M.

Notwithstanding the provisions of S.M.M. Clause S2 (a) preparatory work such as

hacking concrete, racking out joints for key etc., shall be deemed to be included.

Prices for paving shall include for any extra thickness consequent upon the floor not

being finished to the true levels and also for all temporary rules and for all

formwork to stop pavings at openings or edges as required. Prices for tile and

similar paving shall include for any pointing to exposed edges.

Plastering to walls has been measured over concrete columns lintols, etc., flush with

wall face, and prices for plastering shall include for any necessary dubbing out

consequent upon surfaces not being finished to true levels.

MATERIALS

A. SAMPLES

The contractor shall prepare at his own cost sample areas of the paving, plastering

and rendering as directed until the quality, texture and finish required is obtained and

approved by the Architect after which all work executed shall conform with

respective approved sample.

B. CEMENT

Shall be as described in “Concrete Works”

C. LIME

Shall be as described in “Walling”

D. SAND

The sand shall be as described for fine aggregate in “Concrete Wrk” and shall be well

graded to a suitable fineness in accordance with the nature of the plaster or paving in

order to obtain the finish directed.

D. WATER

Shall be as described in “Concrete Work”.

E. WATERPROOFING, COLOURING AND HARDENING COMPOUNDS

All waterproofing, colouring and hardening compounds are to be used strictly in

accordance with the manufacturer’s printed directions.

F. BONDING

Bonding compounds, etc., for use in applying plaster and similar finishes direct to

surfaces without the use of backings or screeds are only to be used if approved by the

Architect and are to be used strictly in accordance with the manufacturer’s printed

instructions.

G. EXPANDED METAL LATHING

Expanded metal lathing shall be 22 gauge 9mm mesh ribbed lathing as B.S. 1369

dipped in asphaltum paint. The edges of sheets to be lapped 50mm and joints

staggered and sheets to be fixed at 500mm centres to all supports with heavy

galvanised staples, or wired with galvanised steel wire.

WORKMANSHIP

H. CHASES, OPENINGS AND HOLES

All chases, holes and the like which were not formed in the concrete or walling shall

be cut, and all service pipes shall be fixed and all hole and chases filled with mortar

before paving and plasterwork is commenced. In no circumstances will the

Contractor be permitted to cut chases, holes and the like in finished pavings or

plasterwork.

A. PROPORTIONS OF MIXES

A mix referred to a 1:4 shall mean 1 cubic metre (1498Kgs) of cement to 4 cubic

metres of sand and other mixes shall be construed in like manner.

B. MIXING

All materials for pavings and plastering must be measured in proper gauge boxes in

the proportions specified and mixed in an approved power driven mixer for not less

than two minutes per batch. The mixer shall be used as close as practicable to the

works and no partial set materials shall be used or remixed.

C. PREPARATION FOR AND FINISH TO IN-SITU PAVING

(i) Where practicable in-situ paving and screeds are to be laid while

the concrete is still green. When this is not practicable the

concrete is to be well washed and brushed perfectly clean with a

steel wire brush, to remove all laitance and to give a roughened

face as a key and then kept wet for at least seven days before the

paving is laid and on the day of laying the surface is to be only

damp with all surplus water removed and painted with cement and

sand (1:1) grout immediately before commencing the paving. The

grout is to be applied continuously in front of the paving and not

in large areas that will dry out before the paving is applied. All

paved surfaces shall be finished hard and smooth with a steel

trowel unless otherwise specified.

(ii) Paving shall be protected during the first stage of hardening from

the harmful effects of sunshine, dry winds, rain or water. In

exposed positions they are to be covered with well wetted layer of

saw dust, hessian or other approved material and this layer is to be

kept damp for at least seven days, during which period no traffic is

to be allowed over the paving. When floor tiles or similar finishes

are to be applied, care shall be taken to protect the screeds to

receive them. When no longer required as protection to the

surface the material is to be removed and the paving left clean and

perfect.

D. ROOF SCREEDS GENERALLY

Roof screeds are to be laid to falls and currents of 1:80 with a minimum thickness of

20mm at rainwater outlets, and are to be finished to the entire satisfaction of the

specialist executing the waterproofing to roof.

E. CEMENT AND SAND ROOF SCREEDS

Roof screeds are to be of cement and sand mixed in the proportions of 1 cubic metre

of cement to 5 cubic metres of sand. The surfaces of the screed is to be

trowelled perfectly smooth to receive other roofing finishes.

F. SCREEDS TO RECEIVE FLOOR AND WALL FINISHES

These are to be finished with a steel trowel to a hard smooth, true and level surface.

Screeds to receive tiles, etc. which are to be bedded in mortar are to be well scratched

to form a key.

A. CEMENT AND SAND PAVING

To be of cement and sand (1:4) laid in one operation and finished hard and smooth

with a steel trowel.

B. WATER PROOF CEMENT SCREEDS

To be as last waterproofed with “Sealocrete Double Strength Pre-mix Solution”

mixed at the rate of 2.25 litres to each 50Kgs. of cement.

C. PRECAST CONCRETE PAVING SLABS

To be all in accordance with B.S. 368. The slabs are to be of the sizes given herein

and bedded, jointed and pointed in cement lime mortar (1:2:9).

D. QUARRY TILE PAVING

Quarry tiles are to be 19mm x 150mm x 150mm, hard, well burned and of an

approved colour to be equal to a sample submitted to and approved by the

Architect.

The tiles are to be soaked in clean water and drained off before bedding and are to be

bedded and jointed in cement and sand (1:4) mortar with 1.5mm joints and to be

cleaned off with sawdust immediately after laying.

E. WOOD PARAQUET

Wood parquet flooring shall be approved hardwood as specified and executed by

an approved specialist subcontractor.

F. P.V.C. TILE FLOORING

Tiles shall be laid by an approved flooring Specialist to patterns as directed by the

Architect using adhesives recommended by the manufacturer in writing. The tiles

shall be laid with straight joints in each direction. Upon completion the floors shall

be thoroughly cleaned and twice machine polished using a polish recommended by

the tile manufacturer.

G. CERAMIC TILE PAVING

Ceramic tile pavings and matching skirtings and nosings are to be laid on

prepared screeds. The tiles are to be soaked in clean water for at least six

hours before use and bedded in cement and sand (1:4) approximately 3mm

thick with straight joints in each direction. Upon completion grout in

matching cement to match tiles and wash and clean down. Tiles are to be

cut with an electric tile cutting saw.

H. TERRAZZO TILE PAVING

To be hard, dense, pressed tiles manufactured from terrazzo as specified hereafter

and in colours to be selected by the Architect. The tiles are to be laid on a prepared

screed and soaked in clean water for at least six hours before use and bedded in

cement and sand (1:4) approximately 2mm thick with straight joints in both

directions. Upon completion grout joints in matching coloured cement and machine

grind and polish.

A. GRANOLITHC AND TERRAZZO PAVING AND WALL FINISHES

Generally

Construction joints between bays of pavings are to be straight and vertical and are to

coincide, as far as possible with those in the concrete under.

After spreading and before finally striking to screed levels the pavings, etc., are to be

lightly tamped, each stage of the laying operation is to be properly carried out at the

optimum degree of stiffness of the mix so that the aggregate remains correctly

distributed throughout the pavings, etc. and so finished that the surface is true to

level, dense smooth and free of laitance and other defects and blemishes. The use of

dry cement or sand to absorb surplus moisture will not be allowed.

The thickness of the pavings, etc., in these Bills of Quantities include for the

combined screed or backing and the Granolithic or terrazzo finish.

Screed and Backing

To be in cement and sand (1:4) and of appropriate thickness.

B. GRANOLOTHIC

(1) To be composed of 900Kgs. of cement to cubic metre 1:21/2 by

Volume of 6mm to 3mm with not more than 15% to pass No. 50 B.S.

sieve clean blacktrap chippings free of dust, laid or applied to screed or

backing whilst they are still green.

Paving to be 20mm minimum thickness granolithic laid on a screed to

make up full thickness specified and finished hard and smooth with

a steel trowel.

(2) Dadoes to be 9mm minimum thickness granolithic applied to a

backing to make up full thickness specified.

Polished granolithic to be finished with a metal roller and all surplus

Cement lightly brushed off when surface is sufficiently hard to resist

dislodgement of aggregate. When the surface is hard enough it shall be wet

ground using a machine until the aggregate is uniformly revealed and then

well washed with clean water. Any small voids or holes left in the

surface are to be filled with cement grout and rubbed down by hand.

Mouldings etc., not accessible to machines are to be hand rubbed and

polished with carborundum. After an interval of 1 to 3 days the

surface is to be finally machine

ground using a fine abrasive.

C. TERRAZZO

(1) To be composed of one part of Snowcrete, Colourcrete or other

equal and approved white or coloured cement to two parts (1:2) by

volume clean marble chippings well washed and free from dust.

The marble chippings may vary in colour and from 3mm to 20mm

dependant on the effect required and sample areas must be

prepared for the Architects approval.

(2) Pavings to be 20mm minimum thickness terrazzo laid on a screed

to make up the full thickness specified

(3) Dadoes to be minimum thickness 9mm terrazzo applied to a

backing to make up the full thickness specifies.

(4) Polished terrazzo to be finishes as granolithic (4) preceding.

(5) Washed terrazzo to be washed and lightly bruches before final

setting so as not to dislodge any agrregate but to leave a textured

surface.

A. DIVISION STRIPS

To be set in position before paving is commenced and embedded straight and true.

B. PREPARATION FOR AND PROTECTION OF PLASTER FINISHES

(i) All surfaces to be plastered or rendered must be brushed clean with

a wire brush and well wetted before plaster is applied. Concrete

surface are to be well hacked and stone or block walls and hollow

tile soffits are to have joints well raked out clean at least 10mm deep to

form a key before plastering or rendering. All plaster and rendering shall

be kept continuously damp for seven days after application.

Where plasterwork is specified in more than one coat the undercoat

shall be well scored with undercut scratches and shall be allowed to

thoroughly dry and set before application of the subsequent coat.

The plaster work shall be protected during the first stage of hardening

from the harmful effects of sunshine, dry winds, rain or water and

shall be kept damp for at least seven days.

C. REVEALS MOULDING ETC.

All reveals and returns shall be set accurately at ninety degrees or to splays as the

case may be and plastered at the same time as the wall face in which they occur.

Internal angles shall be slightly coved and external angles slightly rounded with

neatly formed mitres.

D. CEMENT PLASTER

(i) Where applied in one coat to be cement sand (1:4) not less than

12mm thick finished with a steel trowel or wood float as

hereinafter specified.

(ii) Where applied in two coats, the first coat to be cement and sand

(1:5) not less that 8mm thick and the second coat to be cement and

sand (1:3) not less that 4mm thick finished with a steel trowel or

wood float as hereinafter specified.

E. TEXTURED EXTERNAL CEMENT PLASTER

To be minimum 15mm thick applied in one coat and finished with a wood

Float to an uneven surface. The texture must be consistent with a sample

panel prepared under the Architect supervision.

A. INTERNAL LIME PLASTER

(i) To be applied in two coats of finish not less 12mm total thickness.

The rendering coat shall be in the proportion of cement, lime and

sand (1:2:9) and the finishing coat not less than 1.50mm thick shall

consist of fine sieved lime putty with 10% of cement thoroughly

incorporated immediately before use, trowelled hard and smooth with a

steel trowel and sprinkled with water during the process.

(ii) The first coat must be must be well scored to form a key and at

least fourteen days elapse between the completion of any portion of

the rendering coat and application of the finishing coat.

B. PLAIN TYROLEAN FINISH

(i) The first coat 13mm thick shall consist of mixture of 1 cubic

metre (1498Kgs.) of Portland cement with 10% of lime added by

volume and four cubic metres of sharp sand, applied direct by

means of trowel and brought to a level finish with a straight board

or rule used in all directions to leave no ridges.

(ii) The finishing coat shall be applied by the medium of a Tyrolean

spraying machine and shall consist of cement and sand, the

proportions of which shall vary with the fineness of the sand and

shall be ascertained by trial. Only sufficient amounts shall be

mixed as can be used within one hour.

(iii) The finishing coat shall be built up in layers to be a total thickness

of 6mm to 10mm to give an approved honeycomb texture and shall

be applied in such a manner as to avoid the layers merging into a solid

mass.

C. “TEXCOTE”

Texcote finish is to be carried out by Texciote Africa (Mfg) Ltd. of P.O. Box 18534,

Nairobi.

D. WALL TILING

(i) Glazed wall tiles shall be of sizes specified herein and in colours

to be selected by the Architect. For exposed edges and angles tiles

with one or two edges glazed shall be used.

(ii) Screed to receive tiles to be 10mm thick of cement and sand (1:4)

well scratched to form a key.

(iii) The tiles are to be soaked in clean water for at lease six hours

before use and fixed by bedding in cement and sand (1:3) with

1.5mm straight joints in each direction.

(iv) Alternatively tiles may be in bedded in “Richafix” or other equal

and approved tile fixing compound applied strictly in accordance

with the manufacturer’s printed instructions. Walls are to be dry

before tiles are fixed and tiles are to be soaked in water before use.

Tiling is to be set and closely straight jointed with 1.5mm joints.

If non-plug tiles are used cardboard or plastic spacer pieces are to

be used to obtain constant joint width.

A. SAMPLE

(i) The Contractor shall prepare samples areas of the paving,

plastering and rendering as directed until the quality, texture and

finish required is obtained and approved by the Architect after

which all work executed shall conform with the respective

approved samples.

(ii) Samples shall be prepared at least four weeks before the work is

commenced.

B. MAKING GOOD

The Contractor shall cut out and make good all cracks, blisters and other defects and

leave the whole of the plaster work perfect at completion. When making good

defects the plaster shall be cut out to a rectangular shape with edges undercut to form

dovetailed key all finished flush with face of surrounding plaster, all at the

Contractor’s expense.

C. GENERAL

Glass for glazing and mirrors shall be of approved manufacture and is to comply with

B.S. 952 in all respects free from flaws, bubbles, specks and other

imperfections.

D. CLEAR SHEET GLASS

The clear sheet glass shall be ordinary glazing quality.

E. PLATE GLASS

Polished plate and Georgian wire polished plate glass to be selected glazing quality.

F. FLOAT GLASS

To be “Pilkingtons” float glass or other equal and approved.

G. OBSCURED GLASS

To be of types described and as approved by the Architect.

H. MIRROR

To be selected glazing quality plate glass mirror s of approved manufacture and

fixed at all corners to walls with rawplugs and brass screws with removable

chromium plated dome heads.

I. PUTTY

(i) The putty for glazing to wood sashes is to be linseed oil

and powdered whiting free from grittness putty all as B.S.

544 (Type 1 putty).

(ii) The putty for glazing to metal windows is to be gold size

metal window putty specially designed for tropical use,

all as B.S. 544 (Type 2) putty or patent mastic putty if

approved by the Architect.

(iii) All putty shall be delivered on site in the original

manufacturer’s sealed cans or drums and used direct

therefrom, with the addition only of pure linseed oil if

necessary. No mineral or other oils may be used in the

putty except genuine linseed oil.

A. GLAZING

(i) Glass panes shall be cut to sizes to fit the openings with

not more than 1.5mm play all round.

(ii) The rebates of all windows shall be painted one coat

before puttying.

(iii) All glazing to wood frames shall be sprigged and glazing

to metal frames shall be clipped.

(iv) All glass fixed to aluminium windows to be fixed in

accordance with the manufacturer’s instructions.

(v) All glass, where fixed with putty is to be back and front

puttied and care must be taken to ensure that it does not

project beyond the sight lines of panes and is to be neatly

mitred at angles.

(vi) Putty which has not set hard within seven days must be

removed and the glass re-puttied at the Contractor’s

expense.

B. BEDDING STRIPS

Washleather, velvet, etc. bedding strip to edges of glass is to be of sufficient width

to be turned over 6mm to each side of pane and shall be trimmed to the sight lines

of the pane.

C. GENERALLY

Allow for removing all cracked or broken panes of glass, cleaning rebating and re-

glazing with new glass throughout the progress of the works and for cleaning all

glass on both sides and leaving perfect upon completion.

D. PRICING NOTES

Each pane of glass has been measured to the nearest 25mm above both with in

width and height. Louvre blades have been similarly measured in regard to length.

Prices for glazing shall include for painting rebates of frames before fixing.

PAINTING AND DECORATING

E. MATERIALS

(i) The primers, paints, plastic emulsion coating, are to be approved

by the Architect and the manufacturer must guarantee to give all

times any necessary technical advice called for by the Architect.

(ii) The materials for other finishes be of best quality available of

approved manufacture.

(iii) Before commencing painting, the Contractor shall submit to the

Architect for approval a list of all the brands of paints and

finishing including the necessary primers and undercoats he

intends to use and immediately upon being so approved orders

shall be placed and total requirements obtained for the works.

(iv) Once approved no other brand of material shall be used without

the express permission of the Architect in writing.

A. MORDANT SOLUTION

All galvanized metalwork to be painted shall first receive a coat of a proprietary

mordant solution.

B. KNOTTING

To be shellac knotting to B.S. 1336.

C. STOPPING

To be composed of linseed oil putty, white lead, and gold size suitably proportioned

and mixed.

D. WAX POLISH

Wax polish is to be furniture polish of an approved proprietary brand.

E. SUPPLY AND PREPARATION

(i) All paints, distempers, etc, shall be delivered on site intact in the

original drums or tins and shall be mixed and applied strictly in

accordance with the manufacturer’s printed directions. The only

additions which will be allowed to be made will be liquid thinners,

driers, etc, supplied by the makers for the purpose. No paint,

distemper, etc shall be thinned more than approved by the

Architect.

(ii) Paint for external work shall be of the special quality

recommended by the manufacturers for external use.

F. GENERAL WORKMANSHIP

(i) The priming and undercoats shall be the correct brands and tints

to suit the respective finishings coats all in accordance with the

manufacturer’s directions.

(ii) All surfaces must be thoroughly cleaned down prior to painting

and decorating work, and no external painting may be done in

rainy weather. All paint must be thoroughly well worked on and

excess of paint in any coat must be avoided.

(iii) All brushes, tools and receptacles are to be kept clean and free from

dirt or old paint and are to be thoroughly cleaned each time after use.

(iv) Each coat is to be well brushed into the surface so that every part,

including joints, angles, etc, is adequately covered, but care is to

be taken to avoid excessive or uneven thickness of paint film,

particularly at edges and in angles, etc.

(v) Each coat of paint, etc shall be properly dry and shall be well

rubbed down with fine sand paper and be brushed clean before the

next coat is applied. The paint work shall be finished smooth and

free from brush marks.

(vi) Where so required or directed, painting shall be in part colours

and picked out and cut in and prices shall include for this.

(vii) All ironmongery, metal or plastic plates and electrical outlets and

fittings and the like shall be removed before painting is

commenced, and re-fixed on the completion of the work.

(viii) No spray or roller painting will be allowed unless permission is

given by the Architect.

(ix) The contractor shall so arrange his programme of work that all

other trades are completed and away from the area to be painted

when painting begins.

A. SAMPLE COLOURS

All colours will be selected by the Architect from the B.S. Range of colours.

Samples and colour cards of all paints, distempers, and materials shall be submitted

for approval of the Architect before the same are applied and sample panels shall be

executed for the Architect’s approval where and when directed. Such samples when

approved shall become the standard for the work.

B. PREPARATION AND PRIMING OF PAINTED SURFACES

(a) Plastered surfaces

(i) Plaster surfaces are to be perfectly smooth, free

from defects and ready for decoration. All such

surfaces shall be allowed to dry for a minimum

period of four weeks and rubbed down with No.2

grade sand paper to remove trowel marks stains,

etc., after the priming coat all cracks and

imperfections are to be made good with

“Polyfilla” (or similar approved hard filler) well

rubbed down and then touched up with the

priming coat.

(ii) Priming for plastic emulsion paint shall be the

paint thinned with 25% water.

(iii) Priming for oil paint shall be with an alkali-

resistant primer

(b) Cement plastered, Concrete and Block wall surfaces

(i) Surfaces shall be brushed so as to be entirely free

of dust, dirt, loose material, etc., immediately

prior to decorating.

(ii) Priming for plastic emulsion paint shall be the paint

thinned with 25% water

(iii) Priming for oil paint shall be with an alkali-resistant

primer.

(c) Ferrous Metalwork

All surfaces shall be thoroughly brushed down with wire brushes to

remove all scale, rust, etc., and rubbed down with No. 2 grade sand

paper and brushed and left perfectly clean immediately prior to

decorating.

(i) Shop-primed Surfaces to receive oil paint shall

have all bare places touched up with approved

metal zinc chromate primer.

(ii) Unprimed surfaces shall be given one coat

primer as last.

(iii) Galvanised surfaces shall be treated before

painting with mordant solution. The surfaces

shall then be thoroughly washed down with

clean water, allowed to dry and primed as last.

(iv) Coated surfaces already treated with bituminous

solution shall receive an insulating coat of anti-

bitumen primer or shellac knotting.

(d) Asbestos cement surfaces

(i) All asbestos cement is to be thoroughly brushed

down immediately prior to painting.

(ii) Priming shall be with an alkali-resistant primer.

(e) Fibreboard Surfaces

(i) Surfaces shall be lightly brushed to remove all

dirt, dust and loose –particles and have all nail

holes or other defect stopped with an approved

stopping compound, rubbed down smooth and

left with a texture to match surrounding

material. Nail heads shall be treated with zinc

chromate primer prior to stopping.

(ii) Priming for plastic emulsion paint shall be the

paint thinned with 25% water.

(iii) Priming for oil paint shall be with an alkali-

resistant primer.

(f) Hardboard surfaces

(i) Priming for plastic emulsion shall be the paint

thinned with 25% water.

(ii) Priming for oil paint shall be with a thin oil

primer.

(g) Wood surfaces to receive paint

(i) The woodwork shall have all knots or resinous

parts carefully treated with self knotting a

luminium primer. All cracks, nails or other

holes shall be thoroughly cleaned out and after

priming, all such cracks etc., are to be filled with

matching hard stopping which is to be rubbed

down flush with the adjoining surface.

Priming for oil paint shall be with self knotting

aluminium Primer.

The bottom edges of all joinery work is to be

primed before fixing.

(iv) The back of all joinery work is to be primed

before fixing.

A. PREPARATION, PRIMING ETC. FOR WOOD SURFACES TO

RECEIVE CLEAR TREATMENT

(i) All wood surfaces to receive clear treatment such as varnish,

polyurethane etc., shall be rubbed down to a satin finish with fine

sandpaper immediately prior to application.

(ii) The first coat of polyurethane or similar clear treatment is to be

well rubbed in with a cloth pad and the successive coat applied by

brush. Each successive coat ( except final coat) to be lightly

rubbed with fine steel wool.

B. COVERING UP AND PROTECTING

Cover up all floors, etc. as far as is practicable with dust sheets when executing all

painting and decorating work.

C. LEAVE CLEAN

Paint splashes, spots and stains shall be removed from floors, woodwork, etc. and

damaged surfaces touched up and the whole of the woodwork left clean and

perfect upon completion to the satisfaction of the Architect.

REPAINTING EXISTING PAINTED SURFACES

A. GENERAL PREPARATION

The Contractor is to carefully examine all surfaces to be redecorated for sign of any

defects in the underlying structure. Signs of any dampness, alkali action and loose

or unsound plasterwork, loose putty etc., are to be reported to the Architect before

any further work on that area is put in hand.

B. PREPARATION OF PLASTERED SURFACES

a) To be repainted with plastic emulsion or distemper

After general examination of surfaces for defects as above, the surfaces are

to be washed and brushed down with a stiff fibre brush to remove dust or

dirt preparatory to applying paint and all small cracks are to made good

with hard stopping.

b) To be painted with oil paint

After general examination for surfaces of defects as above, the surfaces are

to be washed and brushed down with stiff fibre brush to remove dust or dirt

preparatory to applying paint and all small cracks are to be made good with

hard stopping.

Rub down paint which, in the opinion of the Architect, is sound, firmly

adhering and without sign of underlying defect, with waterproof glass paper

as required to form a good key, rub down crazed, flaked, peeling blistered,

loose and rough local patches as required to produce a fair and even surface

throughout, remove all defective paint and wash down with clean water.

Bring forward local areas from which paint has been removed and other

slight irregularities with alkali-resistant primer, filler and one undercoat, all

as previously described.

Touch up filling to cracks, etc., with alkali-resistant primer and an

undercoat, all as previously described.

C. PREPARATION OF METAL SURFACES

To be repainted with Oil Paint

Wire brush or scrub as required to remove all rust and all crazed, flaked, peeling,

blistered, loose and perished paint. The metal under such areas is to be left bare and

clean.

Paint which, in the opinion of the Architect, is soundly adhering and without sign of

underlying rust, may be left on but is to be well rubbed down to form a sound key for

the new paint.

All bare surface exposed by the above preparation are to be primed and painted one

undercoat before the main first coat is applied.

A. PREPARATION OF WOOD SURFACES

(a) To be repainted with Oil Paint

(i) Thoroughly clean all paint which, in the opinion of the Architect

is sound, firmly adhering and without sign of underlying defects

and afterwards rub down with pumice stone or waterproof glass

paper and rinse down with clean water. Cleaning is effected by

washing down with suitable detergents (of such dilution that the

paint is not adversely affected) followed by thoroughly rinsing

with clean water. The cleaning agent is to be applied from the

bottom upwards and the rinsing is to be from top downwards.

(ii) Thoroughly examine for defects in the woodwork and sterilize

areas on which there is mould, and re-putty sashes, etc. as

necessary.

(iii) Except as provided in (iv) hereafter, remove all which is crazed,

laked, peeling, blistered, loose and decayed or otherwise defective

by carefully burning off or removing with an approved paint

stripper well rub down as required to produce a fair and even

surface throughout and rinse down with clean water.

(iv) Rub down with pumice alone or waterproof glass paper all paint

which is sound apart from uniform chalking of the surface and

rinse down with clean water.

(v) Thoroughly clean out all cracks, crevices, open joints, holes, etc.

coat with appropriate priming paint and fill in with hard stopping.

When stopping has set rub down until flush with the adjoining

surfaces.

(vi) Cut out all loose knots and stop as described in (v) above and

thoroughly coat all exposed sound knots with knotting.

(vii) Touch up with priming paint and undercoat all surfaces which on

completion of the foregoing preparations are bare of paints and

bring forward local areas from which defective paint has been

removed and other slight irregularities with prime, filler and

undercoat as previously described.

(b) To be redecorated with Polyurethane

Thoroughly clean all existing surfaces and rub down with pumice stone or waterproof

glass paper and rinse with clean water.

B. PRICING NOTES

Prices must include for rubbing down with glass paper between successive coats and

all cuttings in connection therewith. Prices shall include for all work in parti-colours

and for all picking out and cutting in connection therewith.

EXTERNAL WORKS

A. GENERALLY

The specification of works and materials in this section which repeat similar work in

preceeding bills shall be deemed to be the full specification of work and materials

contained in the preceding bills.

B. MURRAM

To be clean hard murram free from loam, top soil or clay.

C. HARD FILLING

To be crushed rock, broken brick, broken concrete or other approved hard granular

materials broken to pass not greater than a 150mm ring or to 75% of the finished

thickness of the layers being compacted whichever is less and graded so that it can be

easily and thoroughly compacted by rolling. The filling is to be laid in layers each of

a consolidated thickness of not exceeding 225mm.

D. ROAD AND PARKING AREA CONSTRUCTION

(a) Preparation of Formation

(i) Properly shape formation surface and consolidate and regulate to

an even and uniform gradient parallel to the ultimate finished

surface.

(ii) All soft spots are to be excavated and filled with hard filling

thoroughly consolidated.

(b) Compaction of Filling

Each layer of hard filling is to be compacted with a smooth faced three

wheel or tandem roller of a weight to be specified by the Architect. Rolling

will continue until the Architect is satisfied that no further compaction can

be achieved but in no case to be less that eight passess of the roller.

(c) Surface finish to filling

The surface of filling shall be blinded with graded quarry chips sufficient to

fill all interstices and rolled as above to proper falls, gradients and cambers.

E. DOUBLE SEAL PAVING

(i) All loose material shall be brushed from the surface of the base

course which shall then be lightly dampened. The surface shall

then be primed with a bitumen emulsion at the rate of 0.85 square

metres per litre.

(ii) Approved 80/100 straight run bitumen shall be heated in a mobile

oil or wood fired boiler having a minimum capacity of 650 litres.

(Note - heating in a drum over an open fire will not be permitted)

and then shall be applied at a temperature of between 1700C and

1800C at the rate of 0.65 square metres per litre.

(iii) Immediately following the bitumen spray, evenly spread 13mm

blacktrap chippings at the rate of 55 to 65 square metres per ton to

give a constant spread and complete adhesion to the bitumen and

roll with a 6/8 ton Tandam roller.

(iv) After an interval of 24 hours, apply second seal as above only at

the rate of 0.84 square metre per litre and then apply a second

layer of 13mm blacktrap chippings and roll as described.

A. PREMIX SURFACE TREATMENT

(i) Stone

The stone shall be hard, dense stone of a uniform blue/grey colour and shall

be free from dust impurities, overburden or admixture of softer stone. It

shall withstand when wet a crushing stress of 4,000 Lbs. Per sq. in. and its

aggregate value shall not exceed 20%. It shall be crushed so as to provide a

material of generally cubical shape, and shall be screened to produce to sizes

specified below.

The grading of the road stone for the surface course shall be within the

following limits:-

(a) 39mm (nominal) chippings % passing

Min. Max.

65m square mesh 85% 95%

38mm " " 40% 60%

21mm " " 0% 5%

(b) 19mm (nominal) chippings

19mm square mesh 90%

100%

9mm " " 0% 5%

(c) 13mm (nominal) chippings

13mm square mesh 90%

100%

6mm " " 0% 5%

(d) Screenings

9mm square mesh 90%

100%

6mm " " 0% 5%

(ii) Bitumen Binders and Bituminous Products Generally

The grades of bitumen binders and bituminous products referred to below are usually

described, for the sake of convenience, in terms of the nomenclature used by "The

Shell Company of East Africa." Equivalent grades by other manufacturers will be

approved by the Architect provided that in his opinion, the product is of high quality

an equivalent specification.

Prime and lack Coats Shelmac M.C.O. or M.C.I.

First (seal coat) and Second (wearing surface) Coats

Maxphalte 80/100 or Shelmae 500/700

First (seal coat) and Second (wearing surface) coats

Maxphalte 80/100 or Shelmac 500/700

(iii) Priming Coat

Immediately on completion of rolling, the surface of the base course shall first be

well watered and then primed with Shelmac M.C.O. or equal approved at a maximum

of 6.50 S.M. per 4 litre in the full width of the base course. The work may then be

left and surfaced at the Contractor's convinience.

(iv) Bituminous Cold Aggregate Premix surface Treatment

(a) Bituminous cold aggregate premix shall be applied in two courses, a 38mm

compacted blinder course and 13m compacted topping carpet. Mixing shall be

carried out at 200/2250F in approved power operated plant which shall incorporate a

twin-shaft, paddle mixer. If stored the premix shall not be permitted to have its

temperature reduced below 1800F. Premix shall be spread within 3 hours of removal

from the mixing plant.

(b) 38mm Binder course shall consist of

Percentage

of weight

38mm nominal chippings 93%

Filler 3mm to dust 31/2%

Shelmac 31/2%

(c) 13mm Topping Carpet shall consist of:-

13mm nominal chippings )

two thirds)

Screening one third 92.25%

Shelmac 4.75%

(d) Laying

The Premix shall be laid to the required thickness using an approved machine, and

immediately rolled one pass 4/5 ton roller. After leaving the surface from 4 to 6

hours, the final compaction shall be applied in two passes of a 10/12 ton roller.

A. PRECAST CONCRETE KERBS CHANNELS AND QUADRANTS

(i) Precast concrete kerbs channels and quadrants shall conform in all

respects with B.S. 340.

(ii) They shall be set on 100mm thick concrete base 200mm wider

than their thickness and haunched up back face 100mm high with

similar concrete.

(iii) Kerbs and channels to curves are to be accurately, set out with

radiating heading joints.

B. PRECAST CONCRETE PAVING SLABS

To be precast concrete slabs of the sizes specified in accordance with B.S. 368,

bedded, jointed and flush pointed in cement lime mortar (1:2:9).

DRAINAGE

C. DRAIN TRENCH EXCAVATIONS

Generally

(i) Trenches to be in straight lines and falls as shown on Drawings or

as directed

(ii) The Contractor shall report to the Architect and obtain his

approval when secure bottoms have been reached and are ready to

receive concrete.

Any such work put in hand before receiving his approval shall, if so

required, be removed and new work substituted, after the Architect’s

approval to the excavations has been obtained, all at the Contractor’s

expense.

(iii) The Contractor shall keep all excavations free from water by

pumping, temporary drains or other means as necessary or

directed. Any work damaged by water shall be replaced at the

Contractor’s expense.

(iv) Where rock is used for back filling it is not to exceed 150mm

gauge and all interstices shall be properly filled in with small

pieces and fine binder.

(v) The first back filling in pipe trenches is to be of approved

materials, imported if necessary, free from rock or stone and to be

watered and carefully tamped over around the pipes until they are

covered to a depth of 300mm subsequent filling is to be in 150mm

layers, watered and rammed.

(vi) Mechanical rammers may not be used until the pipes have been

covered to a depth of 1 metre.

(vii) Any disturbances of or damage to the pipes during backfilling must

be made good by the contractor at his own expense.

(viii) Surplus materials is to be laid over the trench to allow for

settlement of filling and may depressions or subsidence below the

level of the adjacent ground shall be filled up, as and when

necessary, until the end of the Defects Liability period.

A. LAYING AND JOINTING CONCRETE BASE DRAIN PIPES

(i) Laying is to be commenced at points of junction with existing

drains or at points of discharge.

(ii) Each line of drain is to be laid in a perfectly straight line to even

gradient.

(iii) Before each pipe is laid, it shall be examined to ensure that the

bore is clean and any foreign material removed. Each pipe shall

be stuck with a wooden mallet to test for soundness, and any

cracked or damaged pipes rejected. Ends of all pipes must be

clean before jointing.

(iv) Immediately after jointing as before described, a tight fitting wad

or scraper shall be drawn several times through the bore of the

pipe joints are to be protected from injury by rain, soil, water, etc.,

until they have set hard.

(v) Plug open pipes and junctions, whenever work is suspended, to

prevent the entrance of rubbish during construction.

B. CONCRETE BEDS AND SURROUND, ETC, TO PIPES

(i) When pipes are bedded on concrete the bed shall be first laid to

correct falls and levels with recess formed in same for the pipe

socket so that the whole of the soffite of the pipe barrel bears

evenly on the bed.

(ii) When the concrete has set, a thin layer of mortar (1:2) shall be

spread on the bed to receive the pipe’s barrel, sufficient to ensure

that surplus is squeezed out when the pipe is laid and finally

adjusted to level. After jointing the recesses around sockets shall

be filled with concrete of the same mix as the bed and the

haunching or surrounding completed.

C. TESTING DRAINS

The contractor will be required to inspect and test each length of drain before any

refilling of the trench takes place.

D. FENCING GENERALLY

The level of the top of fencing is to be as directed by the Architect but is generally to

follow the mean level of the ground on the line of the fencing. Any minor

excavations on the line of the fencing to enable this to be achieved to be allowed for

in the rates.

A CHAIN LINK FENCING WITH CONCRETE POSTS

Fence posts to be concrete Class “D” finishes fair on all exposed surfaces.

Intermediate fence posts shall be paced at 3.00 metres intervals, to be of 125mm x

125mm section tapering to 75mm x 75mm at top and 2800mm long overall.

The post to be reinforced with four 8mm diameter mild steel bars with No. 12

S.W.G. wire binders at 600mm centres and six times holed for wires or fixing bolts.

Raking struts to be of 200mm diameter section and 3000mm long overall with one

end splayed to suit notch in main post. The strut to be reinforced with four 20mm

diameter mild steel bars with No. 12 S.W.G. wire binders at 500mm centres and four

times holed for wires or fixing bolts. At the junction with the main or gate post the

strut is to be bolted on with one 20mm diameter wrot bolt with head, nut and two

washers.

Main posts, spaced at 9.00 metres centres, and corner posts to be of 150mm x 150mm

section and 2800mm long overall. The post to be reinforced with four 10mm

diameter mild steel bars with No. 12 S.W.G. wire binders at 600mm centres, ten

times holed for wires or fixing bolts and twice notched as required to receive end of

raking struts. Two side faces of post to have set of angle cleats and vertical clamp

bars as last described bolted on.

Concrete filling around post bases to be in plain concrete Class “E”.

Intermediate and main post bases to be excavated to allow posts to be let into the

ground for a vertical depth of 750mm and filled with 600mm diameter x 400mm

deep concrete well packed around post, the excavated material to be part returned,

filled and rammed and the surplus removed.

Raking strut bases to be as last but let into the ground for a vertical depth of 600mm

and filled with 450 x 450 x 300mm deep concrete.

Barbed wires to be No. 8 S.W.G. galvanized mild steel fixed complete with all

galvanized staples strainers winding brackets and other necessary fittings. Fasten to

intermediate concrete posts with No. 16 S.W.G. galvanized annealed mild steel wire.

Tying wire for securing chain-link fencing to line wire to be No. 16 S.W.G.

galvanized annealed mild steel wire.

Chain-link fencing to be manufactured from No. 16 S.W.G. galvanized annealed

mild steel wire woven into 50mm mesh with barbed top and 2000mm high or as

specified. The fencing is to be supported by three single and one double (at top) lines

of line wire and fastened to each line at 900mm horizontal intervals with tying wire.

LANDSCAPING AND SITE DEVELOPMENT

B. BUSH CLEARING

All trees, stumps, shrubs, undergrowth and other vegetation shall be completely cut

down and all roots entirely grubbed up and burned at a central point. All arising will

be left on the site for use in the garden development. Where roots are grubbed up in

areas which are to remain at existing ground level the resulting holes shall be filled

up with approved material rammed in 150mm layers up to the existing ground level.

A. GRASSED AREAS

(i) Areas to be grassed shall be cleared of all debris and roots and dug

up to a depth of 300mm.

(ii) Where outcrops of rock or murram occur, these will be covered

with suitable soil to a depth of 150mm.

B. MAINTENANCE

The trees, grass and flowers shall be watered and maintained until well established.

The contractor is advised to include all this in his rates.

C. GRASS PLANTING IN THE WORKS

Grass planting over rock or compacted fill material

Where grass is to be established in areas where decomposed or solid rock or other fill

material exists closer to the finished surface than 200mm, the following grass

planting procedure shall apply.

The rock shall be removed to a depth of 200mm below the finishes surface. The rock

shall then be ripped or otherwise broken up to a further depth of 150mm and lightly

compacted; 200mm of selected red soil shall then be spread over the surface. The

whole shall then be lightly rotavated to obtain a homogenous mixture to a depth of

150mm. Prior to planting, the soil shall be raked and 50 gm each per square metre of

bonemeal and hoof horn meal shall be spread on the surface.

The grass shall be cuttings of approximately 200mm long and shall be planted at

150mm intervals, 150mm bured in the soil. Planting shall be carried out with the aid

of a wooden peg and the soil well rammed around the cuttings.

The grass shall be systematically watered, cut and weeded to maintain it in a healthy

state throughout the maintenance period.

The rate for grass planting over rock shall include for the ripping of the rock,

provision of grass and all subsequent materials, tools, etc.

D. TREES AND PALMS PLANTING

Pits shall be 0.9 metre diameter x 0.9 metre deep. The sides shall be undercut and the

soil mixture shall be as follows:-

4 parts approved red soil

1 part sewage sludge.

These shall be thoroughly mixed together on the mixing ground and specifically set a

side for the purpose. The mixture shall be filled into the pits in 300mm layers,

firming with hard earth rammers at each layer. The surface is to be shaped into a

bowl-depression 200mm deep to assist in watering.

The tree plants are to be at least 0.9 metre high when brought to the works for

planting.

In the two days before planting takes place, each pit is to be thoroughly soaked with

100 litres of water. The trees or palms shall be planted and sticked in an approved

manner, well watered and maintained throughout the maintenance period.

The rates for tree planting shall include for provision of plants and materials

described in this clause.

A. PLANTING SHRUBS

Pits for shrubs shall be 750mm diameter x 750mm deep. They shall be excavated,

refilled, planted, maintained and paid for identical manner to trees and palms. All

shrubs are grouped together and the tenderer is to give a uniform rate that covers the

cost of any of the shrubs.

B. HERBACEOUS BORDERS, PLANT BOXES AND SIMILAR AREAS

Plant boxes, herbaceous borders and similar areas shall be excavated, refilled,

planted, maintained and paid for in an identical manner to trees and palms, excepting

that four parts of forest soil shall be used in place of red soil and 50 gm each per

square metre of bonemeal and hood and horn meal shall be spread on the surface of

the soil mixture before planting.

C. BOUGANVILLEA HEDGES AND TABLES

Bouganvillea hedges and tables formed on fencing and fencing tables shall be planted

between 100mm diameter cedar fence posts in a pit 0.75 metre deep and 0.75 metre

diameter filled as described above.

For tables, one plant is to be planted every 10 square metres as directed by the

Architect.

Bouganvillea hedge plants are to be planted at 2.0 metres intervals. The cedar posts

are 600mm high and placed at 2.0 metres centres with barbed wire stacked at the top.

Bouganivillea plants are to be attached to the fence wires and strained into a hedge or

table in the course of the maintenance period to the approval of the Architect. The

plant pits are to be excavated, refilled, planted, maintained and paid for in accordance

with the requirements laid down for shrubs.

The rates for bouganivillea plants and hedges and tables shall also include for all the

materials and operations described in this clause. Fence for bouganvillea hedges are

measured lineally and fence tables are measured superficially over the area formed

by the outermost wires of the table.