SPECIFICATION AND

ESTIMATION BY MAHIMA AGARWAL

ROHAN ARORA

BRICK WORK

Brick walls are constructed by joining bricks with cement mortar in arrangements called English Bond, Flemish Bond or Rat Trap Bond.

These bonds give different external appearances to the wall.

All construction systems of brick walls are such devised that vertical cross joints in any layers are staggered.

The bricks thus bonded form a solid mass that does not split when the wall is loaded with live loads and dead loads.

Classification of Brick Work

The classification of brick work according to the

quality of brick is following.

First class brick work

Second class brick work

Third class brick work

First Class Brick Work

First class brick work is made by using first class bricks and cement mortar.

This brick work is used for load bearing walls.

It is made in rich mortar in which the cement and sand ratio is from 1:3 to 1: 6.

First class bricks are identified by their uniform color and a ringing sound when struck.

The bricks are equal in size and have even edges and surfaces.

These bricks do not chip and dont have any cracks.

First class bricks do not absorb water more than 1/6 of their weight.

There is no salty residue when the bricks are dry.

First class bricks have a minimum crushing strength of 105.kg. Per sq. cm

Second Class Brick Work

Second class bricks work is made by using second

class bricks and cement mortar.

These bricks also have the property of first class

bricks but are not very regular or even in shape.

These bricks should not be used for load bearing

walls for more than two storey buildings.

Second class bricks have minimum crushing strength

70.kg per sq. meter.

Third class brick work

This type of brick work is made by using third class

bricks and cement mortar or mud mortar.

Third class brick work is not made in any Govt.

work.

Generally this type of brick work is made for

temporary work in private sector.

Specifications

In the event of use of traditional bricks of nominal size 230mm x 115mm x 75mm with tolerance upto +3 mm in each dimension, one brick and half brick walls shall be considered as 230 mm and 115 mm respectively.

Bricks shall be sound, hard, homogenous in texture, well burnt in kiln without being vitrified, hand/machine moulded, deep red, cherry or copper coloured, of regular shape and size & shall have sharp and square edges with smooth rectangular faces.

The bricks shall be free from pores, cracks, flaws and nodules of free lime.

Hand moulded bricks shall be moulded with a frog and those made by extrusion process may not be provided with a frog.

Bricks shall give a clear ringing sound when struck and shall have a minimum crushing strength of 35 N/mm, unless otherwise specified in the item.

The average water absorption shall not be more than 15 per cent by weight.

Bricks, which do not conform to this requirement, shall be rejected. Over or under burnt bricks are not acceptable for use in the works.

Sample bricks shall be submitted to the ENGINEER for approval and bricks supplied shall conform to approved samples.

If demanded by ENGINEER, brick samples shall be got tested as per IS:3495 by CONTRACTOR at no extra cost to IOCL.

Bricks rejected by ENGINEER shall be removed from the site of works within 24 hours.

Workmanship

Workmanship of brickwork shall conform to IS: 2212. All bricks shall be thoroughly soaked in clean water for at least one hour immediately before being laid.

The cement mortar for brick masonry work shall be as specified in the respective item of work.

Brick work 200 mm/230 mm thick and over shall be laid in English Bond, unless otherwise specified.

For laying bricks, a layer of mortar shall be spread over the full width of suitable length of the lower course. Each brick shall be slightly pressed into the mortar and shoved into final position so as to embed the brick fully in mortar.

Only full size bricks shall be used for the works and cut bricks utilised only to make up required wall length or for bonding.

In the event of usage of traditional bricks of size 230 mm x 115 mm x 75 mm, the courses at the top of the plinth and sills as well as at the top of the wall just below the roof/floor or slabs and at the top of the parapet shall be laid with bricks on edge.

Payment

Measurement shall be in cu.m correct to two places

of decimal for brickwork of thickness one brick i.e.

200 mm/230 mm and above.

RCC SPECIFICATIONS

Ratios of RCC

Various Ratios of RCC :RCC denotes Re-in forced Cement Concrete in which cement, sand and Bajri are laid with the help

of mild steel. This is most important part of the structure. Generally 1:2:4 and 1:1.5: 3 ratios of RCC are used in

construction work.

RCC 1:2:4 Where cement concrete 1:2:4 is used; it means 1 part of cement 2 parts of fine aggregate/coarse sand and 4

parts of coarse aggregate. This ratio of cement concrete gives high strength of cement concrete and is recommended for

following works.

For general RCC work in buildings

Bed plates

Lintels

RCC shelves

Pavement etc.

RCC 1:1.5:3Where cement concrete 1:1.5:3 is used; it means 1 part of cement 1..5 part of fine aggregate/coarse sand and 3

parts of coarse aggregate. This ratio of concrete also gives very high strength of cement concrete and is recommended for

following works.

Structure carries in heavy loads

Important RCC structure such as columns, beams, slabs, cantilever, Chhajja, porch, and balcony etc.

Minimize the effects of earth quake.

Gives more strength accordingly if Tor or Ribbed steel is used with cement concrete 1:1.5:3.

Raw Materials for RCC Slab Roof

1. Cement

2. Coarse aggregate

3. Fine aggregate

4. M.S. Steel bar

5. Binding wire

6. Water

7. Shuttering materials such as wooden Ballies, Planks, and Iron Plates etc.

Advantages of RCC Slab

Energy efficient.

Does not catch fire.

Provides solid and durable roofing.

Very versatile and provides greater protection.

Reduces costs of insurance and has resale value.

SLAB THICKNESS

The slabs are spanned across the walls or the beams, as the case may be.

For a span of about three to four meters the slab thickness is usually of the order of 11cm to 12 cm.

RCC slabs have become the most commonly used technique for roofs/ floors wherein, a slab thickness of 125mm to 150 mm is the norm.

For most engineered structures, the slab thickness is determined as per the building design by the structural engineer.

The skilled masons commonly cast slabs of 100mm/125mm thickness.

CONCRETE MIX

The concrete mix is an important aspect of RCC slab because it determines the compressive strength of concrete and also its durability in terms of weather resistance and water permeability.

In engineering practice, the concrete mix is denoted by M15, M20, M25 (and more richer mixes as well). where the number denotes the strength of a cube in N/mm2 of concrete made using similar mix proportions.

The mix proportions should are determined on the basis of the strength requirements of concrete and the grading and size of aggregates. However, ordinarily, the mix proportions are specified as 1:2:4 (M15), 1:1.5:3 (M20), 1:3:6 (M10) - for cement:sand:aggregates.

For instance, 1:2:4 is commonly specified as mix for casting RCC slabs in rural areas, where as less stronger mixes such as 1:4:8 are specified for Plain Cement Concrete applications such as base concrete for footings.

REINFORCEMENT

The reinforcement steel for slabs is normally Tor steel (cold-twisted deformed bars) or TMT (Thermo Mechanically Treated) bars which have recently become more common on account of their better resistance to corrosion.

The bars are available in standard diameters ranging from 6mm to 40mm. The actual specification for reinforcement is calculated on the basis of structural requirements.

However, for most rural applications, where spans normally donot exceed 3.5 metres, 8 and 10 mm dia steel bars are used, the bigger dimater used as main reinforcemment along the span of the slab.

As a general guide, minimum reinforcement in RCC slabs in either direction should not be less than 0.15% of the gross cross-sectional area of concrete and the maximum diameter of main reinforcement should be 1/8th-1/10th of the slab thickness.

Minimum lap length should be 50 times the diameter of bar- 50d

Development length should be at least sixty times the diameter of bar- 60d

Steel should be bent at 45 degree

CONSTRUCTION :

Shuttering

The process of constructing the RCC slab commences by erecting the centering and shuttering.

Wooden shuttering is usually provided for the purpose although steel shuttering is recommended for getting a good under surface of the slab.

Once the shuttering has been laid in a level, it has to be cleaned properly.

Shuttering oil is applied on the top of shuttering plates to ensure thatconcrete, which has to be laid, does not stick to the surface of the shuttering while it is removed

Reinforcement

The reinforcement bars are then laid as per design in both directions and tied properly with binding wire.

Mixing concrete

CONSTRUCTION

Mixing concrete

All raw materials, cement, sand, coarse aggregates and water should be measured as per requirement of mix design

The raw materials are then mixed uniformly, while ensuring that a proper water-cement ratio is maintained which is just enough to impart sufficient workability needed to pour concrete. Ideally, the mixing should be done in a mechanical mixer.

The concete mixer should be allowed to rotate for at least 2 minutes.

Pouring Concrete

The concrete is then laid continuously to the required thickness and compacted using a needle vibrator to ensure that the cement slurry adequately fills the gaps between aggregates. vibrated effectively such that no air gaps are left in the concrete After the concrete has been poured, it should be finished with a steel float to ensure that the top surface is finished smooth and to make fine adjustments for uniform slab thickness.

CONSTRUCTION

Curing

Curing is critical for a good quality concrete slab and is is commonly done by flooding the slab with water after dividing the slab into smaller portions with cement mortar partitions.

The curing of slab should begin the next day of casting and continue for at least 14 days for adequate concrete strength. Inadequate curing will result in poor quality concrete and can undo the benefit of an appropriate mix and good quality mixing and compaction.

De-shuttering

The side shuttering of the slab can be removed after 48 hours. The bottom shuttering should not be removed before 14 days. The under surface of the concrete should be cleaned with steel brushes such that no impurities are left on the surface.

Although the slab should be constructed under the supervision of a professional, the owner should oversee that all the precautions are being taken during construction

RCC BEAM

The detailing of beams is normally associated with:

i) Size and number (or spacing) of bars,

ii) Lap and curtailment (or bending) of bars,

iii) Development length of bars,

iv) Clear cover to the reinforcement and

v) Spacer and chair bars.

The beams are classified as:

According to shape: Rectangular, T, L, Circular etc.

According to supporting conditions: Simply supported, fixed, continuous and cantilever beams

According to reinforcement: Singly reinforced and doubly reinforced

Depth of the beam is determined based on flexural strength and to satisfy the deflection criteria. Generally the ratio of span to depth ratio is kept as 10 to 15 and the depth to width ratio of rectangular be is taken in the range of 1.5 to 2.

must be 25 mm or shall not be less than the larger diameter of bar for all steel reinforcement including links. Nominal cover specified in Table 16 and 16A of IS456-2000 should be used to satisfy the durability criteria.

A beam consists of following steel

reinforcements:

Longitudinal reinforcement at tension and compression face (Min of two 12 mm diameter bar is required to be provided in tension) in single or multiple rows are provided.

Shear reinforcements in the form of vertical stirrups and or bent up longitudinal bars are provided. ( The bar bent round the tensile reinforcement and taken into the compression zone of an RCC beams are called stirrups)

Side face reinforcement in the web of the beam is provided when the depth of the web in a beam exceeds 750 mm. (0.1% of the web area and shall be distributed equally on two faces at a spacing not exceeding 300 mm or web thickness whichever is less)

Arrangements of bars in a beam should confirm to the requirements of clause given in 8.1 and 8.2 of SP34. Bars of size 6,8,10,12,16,20,25,32,50 mm are available in market. Fig.2 shows different types bars used in a beam.

IPS FLOORING

IPS FLOORING

IPS flooring stands for Indian patent stone flooring.(Cement Concrete flooring )

It is a basic type of flooring which provides good wearing properties.

It is generally used for all types of floors

IPS FLOORING SPECIFICATIONS

Mix of concrete used for IPS flooring specification is 1:1.5:3 (cement, sand and stone aggregates).

As per the nature of use the flooring thickness of concrete is decided from 25 mm to 50 mm. It is laid over the concrete base (1:4:8), which is almost 3 to 4 inches thick plain cement concrete (PCC) base.

You can decide the thickness of the IPS flooring as per the requirement of work; in residential floor 75 mm floor thickness is sufficient whereas industrial floor thickness should be kept 150 mm.

MATERIALS

The maximum size of coarse aggregate shall be 10

mm. The fine aggregate shall consist of properly

graded sand.

Concrete shall be mixed preferably by machine,

and hand mixing shall be avoided as far as

practicable.

PREPARATION OF BASE The base concrete surface shall be thoroughly chipped to remove laitance, caked mortar, loose sand, dirt etc.

cleaned with wire brush and washed clean and watered until no more water is absorbed.

Where the base concrete has hardened so much that roughening the surface by wire brushes is not possible,

the same shall be roughened by chipping or hacking at close intervals.

The surface shall be soaked with water for at least 12 hours and surface water removed and dried before

laying the topping.

Before laying the concrete, cement slurry at 2.75 kg./ sqm. of surface shall be applied for better bond.

Concrete flooring shall then be laid in alternate bays in pattern and joints, wide/ flush as per drawing.

The edge of each panel into which the floor is divided shall be supported by wooden or metal strips duly

oiled to prevent sticking.

The panels shall be of uniform size and, unless otherwise specified, no dimension of panel shall exceed 2 m.

and the area of a panel shall not be more than 2 sqm.

However, the exact size of panel shall be decided by the Engineer-in-Charge to suit the size of the room.

The joints in the floor finish shall extend through the borders and skirting/dado. The border shall have mitred

joints at the corners of the room.

Where glass/ aluminium dividing strips are proposed to be provided, the same shall be fixed in cement

mortar 1:2 @ 600 mm. centres or as specified in the schedule for full depth of the finished floor.

The depth of dividing strips shall be the thickness as proposed for the finished floor in the item. In the case of

flush joins, alternate panels only may be cast on same day. At least 48 hours shall elapse before the concreting

of adjacent bay is commenced.

FINISHING THE SURFACE AND STEEL

TROWEL FINISH

Finishing the Surface :

After the concrete has been fully compacted, it shall be finished by trowelling or floating. Finishing operations shall start shortly after the compaction of concrete and shall be spread over a period of one to six hours depending upon the temperature and atmospheric conditions.

The surface shall be trowelled intermittently at intervals for several times so as to produce a uniform and hard surface.

After the concrete in the bays has set, the joints of the panels should be filled with cement cream and neatly floated smooth or jointed.

In case of wide joints the same shall be filled with pigmented cement concrete (1:2:4) using approved pigment and the joint shall be finished in perfectly straight line.

Steel Trowel Finish :

Areas where Marblex tiles are proposed to be used are required to have base concrete finished smooth by steel trowel

CURING AND MEASUREMENT

Curing :

The completed flooring shall be protected from sun, wind and rain for the first two days and movement of persons over the floor is prohibited during this period.

The finished surface shall be covered and cured continuously form the next day after finishing, at least for a period of 7 days.

Curing shall be done by spreading sand and kept damp throughout the curing period.

Mode of Measurement :

The rate for flooring and skirting shall be in square metre of the area covered.

The length and width of the flooring shall be measured net between the faces of skirting or dado or plastered faces of walls which is the proudest.

All openings in flooring exceeding 0.1 sqm. in area where flooring is not done shall be deducted and net areas only shall be measured.

MIXING AND LAYING

Mixing :

The topping concrete shall be of mix of one part of cement, two parts of sand and 4 parts of well graded stone chips of 10 mm. maximum size.

The ingredients shall be thoroughly mixed with just sufficient water to the required plasticity, having water cement ratio not more than 0.4.

Laying :

The free water on the surface of the base shall be removed and a coat of cement slurry

to the consistency of thick cream shall be brushed on the surface. On this fresh grouted base, the prepared

cement concrete shall be laid immediately after mixing. The concrete shall be spread evenly and laid immediately

after mixing.

TERRACE WATER-PROOFING

STEP ONE

Before taking up the water proofing work the construction of parapet walls, including finishing should be completed. Similarly, the ancillary items like haunches, khurras, grooves to tack the fibre cloth layer, fixing up of all down take pipes, water pipes and electric conduits etc.

STEP TWO - Preparing Surface

There is no necessity of hacking the surface but the surface to be treated shall be cleaned including removing the mortar dropping from the surface.

STEP THREE - Providing and Laying of Cement Slurry

The consistency of the slurry should be such as to cover the desired area by using 0.488 kg of blended cement per sqm of area.

On deciding the correct quantity of water required per sqm. area the required quantity of slurry should be prepared which can be applied over the desired surface within half an hour of mixing with 0.488 kg. of grey cement + 0.253 kg. water proofing compound as per manufacturer specifications + x litres of water per sqm. area and the required quantity of slurry thus prepared should only be used for first application.

TERRACE WATER-PROOFING

STEP 4 -Providing and Laying of Fibre Glass Cloth

The fibre glass cloth shall be of approved brand and shall be thin, flexible uniformly bonded mat composed of chemically resistant borosilicate glass fibre distributed in random open porous structure bonded together with a thermosetting resin.

when the slurry applied is still green the fibre glass as specified shall be spread evenly on the surface without any kink and pressed in such a way that no air spaces exist. The fibre glass cloth shall be taken upto a height of 30 cm on parapet walls and tucked in the groove specially prepared at that height.

STEP 5-Providing and Laying of Cement Slurry for Third Layer

This slurry shall be applied evenly on the entire surface covered with fibre glass cloth so that a layer of 1.50 mm thickness of slurry is formed. The application of slurry shall be continued over the 300 mm portion of parapet wall and also the portion tucked in the groove on top.

The entire surface shall be allowed for air curing for 4 hours and later the surface shall be cured with clean water for 7 days.

TERRACE WATER PROOFING INTEGRAL CEMENT BASED WATER PROOFING TREATMENT WITH BRICK BAT COBA

STEP ONE Preparing surface

STEP TWO- Providing and laying of slurry under base coat

STEP THREE - Laying Base Coat 20 mm thick

Immediately after the application of slurry and when the application is still green, 20 mm thick cement plaster as base coat with cement mortar 1:5 (1 blended cement : 5 coarse sand) shall be evenly applied over the concrete surface taking particular care to see that all the corners and joints are properly packed and the application of the base coat shall be continued upto a height of 300 mm over the parapet wall.

STEP FOUR -Laying Brick Bat Coba

Brick bat of size 25 mm to 115 mm out of well burnt bricks shall be used for the purpose of brick bat coba. Brick bats shall be laid to required slope/gradient over the base coat of mortar leaving 15-25 mm gap between two bats.

STEP FIVE - Application of Slurry over Brick Bat Coba

STEP SIX - Laying Finishing Layer (Protective Coat - fibre glass cloth)

STEP SEVEN

Where roof surfaces are expected to be used precast cement concrete tiles or 40 mm thick cement concrete shall be laid on the water proofing treatment.

TERRACE INSULATION WITH CELLULAR CONCRETE

Cellular concrete is a light weight concrete formed by producing gas or air

bubbles in cement slurry or a cement sand slurry. Cellular concrete shall

conform to IS 6598 and shall be of following two types depending on the

manner of manufacture.

Grades - Each of these two types of the material shall have three grades,

namely:

Grade A - Light weight cellular concrete;

Grade B - Medium weight cellular concrete and;

Grade C - Heavy weight cellular concrete.

CELLULAR CONCRETE

TERRACE INSULATION With Expanded Polystyrene

Expanded polystyrene can either be fixed with suitable adhesive to the false ceiling board or else it can simply be rolled over the suspended false ceiling.

Expanded Polystyrene, or EPS for short, is a lightweight, rigid, plastic

foam insulationmaterial produced from solid beads of polystyrene

TIMBER TO BE USED IN

DOOR FRAMES AND SHUTTERS

Timber is classified as under :

(i) Teak wood

(ii) Deodar wood

(iii) Non-coniferous timbers other than teak

(iv) Coniferous timber other than deodar.

First Class Wood

Individual hard and sound knots shall not be more than 25 mm in diameter and the aggregate area of all the knots shall not exceed one per cent of the area of the piece.

Second Class Wood

Individual hard and sound knot shall not be more than 40 mm in diameter and aggregate of all the knots shall not exceed one and half per cent of the area of the piece. Wood shall be generally free from sapwood, but traces of sapwood may be allowed.

TIMBER FOR FRAME WORK AND

SHUTTERS

Timber for stiles and rails shall be of the same species and shall be sawn in the directions of grains. Sawing shall be truly straight and square. The timber shall be planed smooth and accurate to the required dimensions. The stiles and rails shall be joined to each other by plain or haunched mortise and tenon joints and the rails shall be inserted 25 mm short of the width of the stiles. The bottom rails shall have double tenon joints and for other rails single tenon joints shall be provided. The lock rails of door shutter shall have its centre line at a height of 800 mm from the bottom of the shutters unless otherwise specified. The thickness of each tenon shall be approximately one-third the finished thickness of the members and the width of each tenon shall not exceed three times its thickness.

Gluing of Joints : The contact surfaces of tenon and mortise shall be treated, before putting together, with bulk type synthetic resin adhesive conforming to IS 851 suitable for construction in wood

Stiles and bottom rail shall be made out of one piece of timber only. Intermediate rail exceeding 200 mm in width may be of one or more pieces of timber. The width of each piece shall be not less than 75 mm. Where more than one piece of timber is used for rails, they shall be joined with a continuous tongued and grooved joint glued together and reinforced with metal dowels at regular intervals not exceeding 200 mm.

DOOR SHUTTERS

TOLLERERANCE IN DOOR SHUTTERS

Size and Types

The designation refers to modular

sizes of door openings. First

number stands for width and the

last for height in modules (M =

100 mm). Alphabet D refers to

doors, S to single and T to

double leaf shutter.

TOLLERANCE of COMPONENTS

10 WT 12 would mean a

window shutter suitable for a

double shutter window of 10

modules width and 12

modules height.

Tolerances on the overall dimensions

of window and ventilator shutter shall

be + 3 mm.

INDUSTRIAL FLOORING With metallic hardening compound

Wherever floors are required to withstand heavy wear and tear, use of floor hardener shall be avoided as far as possible by using richer mixes of concrete, unless the use of a metallic hardner is justified on the basis of cost. Where metallic hardener topping is used, it shall be 12 mm thick.

Metallic Hardening Compound

The compound shall be of approved quality consisting of uniformally graded iron particles, free from non-ferrous metal particles, oil, grease sand, soluble alkaline compounds

Base layer

Flooring shall be laid on base concrete where so provided. The base concrete shall be provided with the slopes required for the flooring.

The flooring shall be commenced preferably within 48 hours of the laying of base concrete. The surface of the base shall be roughened with steel wire brushes without disturbing the concrete. Immediately before laying the flooring, the base shall be wetted and a coat of cement slurry @ 2 kg of cement spread over an area of one sqm so as to get a good bond between the base and concrete floor.

Under Layer

Cement concrete flooring of specified thickness and mix (mentioned in item for under layer) shall be laid as under layer (11.2.1 and 11.2.4). The top surface shall be roughened with brushes while the concrete is still green and the forms/strips shall be kept projecting up 12 mm over the concrete surface, to receive the metallic hardening compound topping

Topping

This shall consist of 12 mm thick layer of mix 1:2 (1 cement : 2 stone aggregate 6 mm nominal size) by volume or as otherwise specified with which metallic hardening compound is mixed in the ratio of 1 : 4 (1 metallic concrete hardener : 4 cement) by weight. Metallic hardener shall be dry mixed thoroughly with cement on a clean dry pacca platform. This dry mixture shall be mixed with stone aggregate 6 mm nominal size or as otherwise specified in the ratio of 1 : 2 (1 cement : 2 stone aggregate) and well turned over. Just enough water shall then be added to this dry mix as required for floor concrete.