Top Block Design

Design GuideConcrete block masonry

CI/SfBFf

November 1997

2

T o p b l o c k D e s i g n G u i d e

This Topblock Design Guide

contains detailed information

on the design and performance of

constructions using Topblock

products. It draws upon Topblock’s

unrivalled experience, making it an

invaluable reference document.

The guide will assist in the design

of blockwork to meet project

requirements, in compliance

with building regulations,

British Standards and

industry codes of practice.

The blockwork solutions presented

here incorporate the latest research

into concrete blockwork

performance. Five key aspects of

blockwork masonry performance

are dealt with:-

• thermal performance,

• acoustic performance,

• structural design,

• movement control,

• durability.

It includes guidance on the safe

handling of blocks for both the

specification and sitework phases

of projects.

Detailed product information,

including the performance

characteristics

of Topblock products, is

given in the individual

product brochures.

Design Guidec o n c r e t e b l o c k m a s o n r y

1. Thermal performance 4

1.1 Requirements of Building Regulations 4

1.2 Heat Loss 4

1.3 Thermal bridging 7

1.4 Limiting air infiltration 8

1.5 Calculating U values 8

1.6 Wall solutions 8

1.7 Floor solutions 17

2. Acoustic performance 19

2.1 Introduction 19

2.2 Internal layout 19

2.3 Sound insulation 19

2.4 Sound absorption 25

3. Structural design 26

3.1 Design principles 26

3.2 Unreinforced walls 26

3.3 Reinforced walls 31

3.4 Diaphragm walls 32

4. Movement control 33

4.1 The causes of movement 33

4.2 Provision for movement 33

4.3 Summary 38

5. Durability 43

5.1 Frost resistance 43

5.2 Sulphate resistance 43

6. Block handling 45

6.1 Regulations and guidance 45

6.2 Safe handling of blocks 45

3

Contents


1.1 Requirements ofBuilding RegulationsBuilding Regulation L1 requires

reasonable provision be made for

the conservation of fuel and power

in buildings. The Approved

Document to Regulation L1 sets out

ways of meeting the requirements

for energy efficiency for new build

and refurbishment projects. Those

aspects which affect the design and

specification of blockwork include:

• insulation of the building fabric;

• thermal bridging at openings;

• limitation of air infiltration.

The thermal performance

requirements apply to:

• dwellings;

• other buildings with total floor

area exceeding 30m2.

There are two main exclusions from

the requirements:

1.Buildings intended to have low

levels of heating do not have to

comply with the requirements:

low level heating is defined as an

output of:

• not more than 50W/m2 floor

area for industrial or storage

buildings;

• not more than 25W/m2 floor

area for buildings other than

dwellings.

(Where the eventual level of

heating is not known at the time

of construction, the building must

be designed to comply with the

requirements.)

2.For a small extension not

exceeding 10m2 in total floor area,

reasonable provision is deemed to

be achieved if it reaches the same

level of effectiveness as the

existing construction.

1.2 Heat loss1.2.1 Dwellings

Regulation 14A of the Building

Regulations requires the

preparation of an energy rating for

all dwellings which are new build or

created by the material change of

use of an existing building: the

rating must be calculated using the

Standard Assessment Procedure

(SAP). Guidance on calculating SAP

ratings is given in Approved

Document L, Appendix G.

There are three methods for

demonstrating compliance with the

requirement to limit heat loss

through the building fabric:-

• Elemental method;

• Target U value method;

• Energy Rating method:

any one of those methods may

be used.

4


1. Thermal performance

1.2.1.1 Elemental method

To demonstrate compliance using

this method elemental U values

must not exceed those given in

table 1.1. The U values shown in

column (a) apply to dwellings with

a SAP Energy Rating of 60 or less.

Where the SAP rating exceeds 60,

the U values in column (b) should

be used.

1.2.1.2 Target

U value method


this method the average U value of

the dwelling must not exceed the

calculated Target U value.

The Target U value is calculated as:

for dwellings with SAP Rating of 60

or less

and as

for dwellings with SAP Energy

Rating of more than 60

The average U value is calculated

as:

This method allows designers to

trade-off the thermal performance

of different elements and to take

account of benefits from improved

heating efficiency and solar gains.

1.2.1.3 Energy Rating method


this method the SAP rating of the

dwelling must not be less than the

appropriate value shown in

table 1.2.

Dwelling floor area (m2)

85

5


80 or less

More than 80 up to 90

SAP Energy Rating

80

81

More than 90 up to 100 82



More than 120

Table 1.2: SAP values for the Energy Rating method

Total heat loss

Total area of exposed elements

Total floor area x 0.64+ 0.40


Total floor area x 0.57+ 0.36


Exposed walls

Element

For SAP energy ratings of

60 or less: (a) over 60: (b)

0.45 0.45

Exposed floors and ground floors 0.35 0.45

Roofs* 0.20 0.25**

Semi-exposed walls and floors 0.60 0.60

Windows, doors and rooflights*** 3.00 3.30

Table 1.1: Standard U values (W/m2K) for dwellings

Notes *Any part of a roof having a pitch of 70º or more may have the same U value as a wall.

**For rooms in the roof, or flat roof construction a U value of 0.35W/m2Kis acceptable to dwellings.

***The U values given for windows, doors and rooflights (3.0 or 3.3W/m2K) are based on a combined area not exceeding 22.5% of total floor area. However, some flexibility is possible, for example, if improved performance units are used a corresponding increase in area is permitted.

1.2.2 Buildings other thandwellings

There are three methods for

demonstrating compliance with the

requirement to limit heat loss

through the building fabric:-

• Elemental method;

• Calculation method;

• Energy Use method:

any one of those methods may

be used

1.2.2.1 Elemental method


this method elemental U values

must not exceed those given in

table 1.3.

The area of glazing must not exceed

the values given in table 1.4 unless

there is a compensating

improvement in the performance

of the glazed units.

1.2.2.2 Calculation method


this method the rate of heat loss

from a proposed building must be

no greater than that from a notional

building of the same size and shape

which has been shown to comply

using the Elemental method.

This allows greater flexibility than

the Elemental method as the

U values of elements may be varied

within the prescribed limits

(see 1.2.3).

1.2.2.3 Energy Use method


this method the annual energy use

of the proposed building must be

no more than a similar building

which has been shown to comply

using the Elemental method.

This permits the designer to use

any valid energy conservation

measure and to take account of

solar and internal heat gains.

1.2.3 Limiting U values

For compliance methods other than

the Elemental method, the U values

of exposed building elements must

not exceed the limiting values

shown in table 1.5.

Element

Notes *Display windows and shop entrance doors are excluded

Notes *Any part of a roof having a pitch of 70º or more may have the same U value as a wall.

**To buildings comprising a flat roof or insulated sloping roof with no loft space, a U value of 0.45W/m2K will be acceptable or 0.35W/m2K for residential buildings.

6


Building type

Residential including hotels andinstitutional buildings

Places of assembly, offices and shops

Industrial and storage buildings

Vehicle access doors

Windows and doors Rooflights

30% exposed wall area

20% of roof area40% exposed wall area*

15% exposed wall area

As required

Table 1.4: Basic allowance for windows, doors and rooflights

Exposed walls

Exposed floors and ground floors

Roofs*

Semi-exposed walls and floors

Windows, doors and rooflights

Vehicle access and similar large doors

U-value

0.45

0.45

0.25**

0.60

3.30

0.70

Table 1.3: Standard U values (W/m2K) for buildings other than dwellings

Dwellings

Residential buildings

Otherbuildings

Limiting U values (W/m2K)

Walls

0.7

Floors

0.7

0.7 0.7

0.7 0.7

Roofs

0.35

0.45

0.7

Table 1.5: Limiting U values forexposed elements

1.3 Thermal bridgingThermal bridging can occur around

windows and doors, increasing heat

loss and leading to localised surface

condensation.

Approved Document L shows a

number of recommended methods

of avoiding thermal bridging

(reproduced in figure 1.1) as well

as a number of alternatives

(see Appendix D of the

Approved Document).

A method of calculating the effect

of thermal bridging is given in

BRE Information Paper 12/94

“Assessing condensation risk

and heat loss at thermal bridges

around openings”.

7


Notes 1 The thermal conductivity of the blockwork should not exceed 0.16W/mK (eg Toplite Standard) and the frame should overlap the blockwork by at least 30mm for drylining or alternatively 55mm for lightweight plaster.

2 The internal faces of metal lintels should be covered with at least 15mm of lightweight plaster; alternatively they can be drylined

Insulating blockwork 1

Internal insulation

Partial cavity fill 2

Full cavity fill 2

Figure 1.1 Reducingthermal bridging around openings

Cavities and airspaces

1.4 Limiting airinfiltrationApproved Document L contains

recommendations for limiting the

infiltration of cold external air into

buildings: they consist mainly of

sealing potential gaps in the

construction. Dry linings to walls

should be sealed at the perimeters

of openings and at floors and

ceilings by using continuous bands

of plaster or fixing adhesive.

1.5 Calculating U valuesU values may be calculated by using

the tabular method given in

Approved Document L,

Appendix A, or by the proportional

area method given in Appendix B.

Both methods take account of the

effects of repeating thermal bridges.

We recommend calculation on the

basis of known material sizes and

properties as this will result in a more

economical construction.

The bridging effect of mortar joints

in blockwork need be considered

only when the difference in thermal

resistance between block and mortar

is greater than 0.1m2K/W. Thus for

calculation purposes, walls of

Topcrete or of certain sizes of

Hemelite and Lignacite may be

treated as homogeneous leaves.

Ground floor U values may be

calculated using the Perimeter/

Area method (see Approved

Document L, Appendix C).

The area of the floor should be

measured between the finished

internal faces of the building

and should include non-usable

space such as stairwells and

builders’ ducts.

1.6 Wall solutionsThe following tables cover the

constructions most likely to be

used in the design of external walls.

Where U values have been shown

with no finish (NF) the tables assume

the use of Paint Quality or Fair Face

blocks, where those form part of the

product range: Toplite blocks are

available only in a keyed finish.

Hemelite and Topcrete blocks may

be solid, cellular or hollow.

The U values have been calculated

following the recommendations of

Approved Document L and using

the material and airspace values

shown in table 1.6 and 1.7

respectively. All blocks are assumed

to have a face size of 440 × 215mm

with 10mm thick mortar joints.

0.35

8


General materials

Facing brick

Mortar

Render

Dense plaster

Lightweight plaster orplasterboard

Insulation

50mmCrown Dritherm full-fill

65mm

75mm

Rockwool cavity batts

Jablite cavity partial fill

Rockwool HP partial fill

Wallmate CW

Celotex double-R CW2000

Thermal conductivity

(W/mK)

0.84

0.80

0.50

0.50

0.16

0.033

0.034

0.036

0.036

0.037

0.033

0.025

0.019

Table 1.6: Conductivities of materials

Cavity – high emissivity

Cavity – low emissivity

10mm airspace behind plasterboard

25mm airspace behind foil-backed plasterboard

Thermalresistance(m2K/W)

0.18

0.35

0.14

Table 1.7: Resistance values of airspaces

9


U Values (W/m2K) Insulation & Surface Finish

DPNF

50mm Rockwool Batts

λ = 0.036

65mm Rockwool Batts

λ = 0.036

0.40 0.39 0.38 0.37 0.34 0.34 0.33 0.32 0.31 0.31 0.30 0.29

0.35 0.32 0.32 0.32 0.30 0.30 0.30 0.29 0.28

0.34 0.32 0.31 0.31 0.30 0.29 0.29 0.28 0.28

0.35 0.35 0.34 0.33 0.31 0.30 0.30 0.29 0.28 0.28 0.28 0.27

0.43 0.43 0.42 0.40 0.36 0.36 0.35 0.34 0.33 0.33 0.32 0.31

0.39 0.39 0.38 0.36 0.34 0.33 0.33 0.31 0.31 0.30 0.30 0.29

0.46 0.45 0.44 0.42 0.38 0.38 0.37 0.36 0.35 0.34 0.34 0.32

0.42 0.41 0.41 0.39 0.36 0.35 0.35 0.33 0.32 0.32 0.32 0.30

0.53 0.53 0.51 0.48 0.43 0.43 0.42 0.40 0.39 0.39 0.38 0.36

0.51 0.51 0.50 0.47 0.42 0.42 0.41 0.39 0.38 0.38 0.37 0.35

0.53 0.53 0.51 0.48 0.44 0.43 0.42 0.40 0.39 0.39 0.38 0.36

0.52 0.51 0.50 0.47 0.42 0.42 0.41 0.39 0.38 0.38 0.37 0.35

0.56 0.55 0.54 0.51 0.45 0.45 0.44 0.42 0.40 0.40 0.39 0.37

0.54 0.54 0.53 0.50 0. 44 0.44 0.43 0.41 0.40 0.39 0.39 0.37

LP DL DPNF LP DL

75mm Rockwool Batts

λ = 0.036

DPNF LP DL

100mm Toplite GTI

0.38 0.37 0.37115mm Toplite GTI

0.37 0.36 0.36125mm Toplite GTI

140mm Toplite GTI

100mm Toplite Standard


100mm Toplite ‘7’


100mm Hemelite

140mm Hemelite

100mm Lignacite

Table 1.8a: Cavity wall full fill – 103mm brick • full fill insulation • block • finish

140mm Lignacite

100mm Topcrete

140mm Topcrete


DPNF

50mm Injected cavity

insulationλ = 0.039



0.41 0.41 0.40 0.38 0.36 0.35 0.35 0.33 0.33 0.32 0.32 0.31

0.36 0.34 0.34 0.33 0.32 0.31 0.31 0.31 0.29

0.35 0.33 0.33 0.32 0.31 0.31 0.30 0.30 0.29

0.37 0.36 0.35 0.34 0.32 0.32 0.31 0.30 0.29 0.29 0.29 0.28

0.45 0.45 0.44 0.42 0.38 0.38 0.37 0.36 0.35 0.35 0.34 0.33

0.41 0.40 0.40 0.38 0.35 0.35 0.34 0.33 0.32 0.32 0.32 0.30

0.48 0.47 0.46 0.44 0.40 0.40 0.39 0.37 0.37 0.36 0.36 0.34

0.44 0.43 0.43 0.40 0.38 0.37 0.36 0.35 0.34 0.34 0.33 0.32

0.56 0.56 0.54 0.51 0.46 0.46 0.45 0.43 0.41 0.41 0.40 0.38

0.54 0.54 0.52 0.49 0.45 0.44 0.43 0.41 0.40 0.40 0.39 0.37

0.57 0.56 0.54 0.51 0.47 0.46 0.45 0.43 0.42 0.41 0.40 0.38

0.55 0.54 0.52 0.49 0.45 0.44 0.43 0.41 0.40 0.40 0.39 0.37

0.59 0.59 0.57 0.53 0.48 0.48 0.47 0.44 0.43 0.43 0.42 0.40

0.58 0.57 0.56 0.52 0.47 0.47 0.46 0.43 0.42 0.42 0.41 0.39

LP DL DPNF LP DL



DPNF LP DL

100mm Toplite GTI

0.39 0.39 0.38115mm Toplite GTI

0.38 0.38 0.37125mm Toplite GTI

140mm Toplite GTI





100mm Hemelite

140mm Hemelite

100mm Lignacite

Table 1.8b: Cavity wall full fill – 103mm brick • full fill insulation • block • finish

140mm Lignacite

100mm Topcrete

140mm Topcrete

Key to tables • NF – No finish

• DP – Dense plaster

• LP – Lightweight plaster• DL – Drylining on dabs

(9.5mm plasterboard)

Notes • Rendered blockwork may be used as an alternative to facing brick. The U values will be equivalent or better than the values shown.

10



DPNF

50mm Crown

Dritherm battλ = 0.033

65mm Crown


0.38 0.37 0.36 0.35 0.33 0.32 0.32 0.31 0.31 0.31 0.30 0.29

0.34 0.31 0.31 0.31 0.30 0.30 0.30 0.29 0.28

0.33 0.31 0.30 0.30 0.29 0.29 0.29 0.28 0.28

0.34 0.33 0.33 0.31 0.30 0.29 0.29 0.28 0.28 0.28 0.28 0.27

0.41 0.40 0.40 0.37 0.35 0.35 0.34 0.33 0.33 0.33 0.32 0.31

0.37 0.37 0.36 0.34 0.32 0.32 0.32 0.30 0.31 0.30 0.30 0.29

0.43 0.43 0.42 0.40 0.37 0.36 0.36 0.34 0.35 0.34 0.34 0.32

0.40 0.39 0.39 0.37 0.34 0.34 0.34 0.32 0.32 0.32 0.32 0.30

0.50 0.49 0.48 0.45 0.41 0.41 0.40 0.39 0.39 0.39 0.38 0.36

0.48 0.48 0.47 0.44 0.40 0.40 0.39 0.38 0.38 0.38 0.37 0.35

0.50 0.49 0.48 0.45 0.42 0.41 0.40 0.39 0.39 0.39 0.38 0.36

0.48 0.48 0.47 0.44 0.41 0.40 0.39 0.38 0.38 0.38 0.37 0.35

0.52 0.52 0.50 0.47 0.43 0.43 0.42 0.40 0.40 0.40 0.39 0.37

0.51 0.51 0.49 0.47 0.42 0.42 0.41 0.39 0.40 0.39 0.39 0.37

LP DL DPNF LP DL

75mm Crown


DPNF LP DL

100mm Toplite GTI

0.36 0.36 0.35115mm Toplite GTI

0.35 0.35 0.34125mm Toplite GTI

140mm Toplite GTI





100mm Hemelite

140mm Hemelite

100mm Lignacite

Table 1.8c: Cavity wall full fill – 103mm brick • full fill insulation • block • finish

140mm Lignacite

100mm Topcrete

140mm Topcrete


DPNF

25mm Jablite

λ = 0.037

40mm Jablite

λ = 0.037

0.43 0.40 0.39 0.38 0.37 0.36 0.35 0.35 0.33

0.42 0.38 0.38 0.37 0.36 0.35 0.34 0.34 0.32

0.44 0.43 0.42 0.40 0.37 0.36 0.36 0.34 0.33 0.33 0.33 0.31

0.56 0.55 0.54 0.51 0.46 0.45 0.44 0.42 0.41 0.40 0.40 0.38

0.50 0.49 0.48 0.45 0.41 0.41 0.40 0.38 0.37 0.37 0.36 0.35

0.61 0.60 0.58 0.54 0.49 0.48 0.47 0.44 0.43 0.42 0.41 0.40

0.54 0.53 0.52 0.49 0.44 0.44 0.43 0.41 0.40 0.39 0.38 0.37

– – 0.70 0.65 0.57 0.56 0.55 0.52 0.49 0.49 0.48 0.45

0.70 0.69 0.67 0.62 0.55 0.54 0.53 0.50 0.48 0.47 0.46 0.44

– – 0.70 0.65 0.57 0.56 0.55 0.52 0.50 0.49 0.48 0.45

– 0.69 0.67 0.62 0.55 0.54 0.53 0.50 0.48 0.47 0.46 0.44

– – – 0.69 0.60 0.60 0.58 0.54 0.52 0.51 0.50 0.47

– – – 0.67 0.58 0.58 0.56 0.53 0.51 0.50 0.49 0.46

LP DL DPNF LP DL

50mm Jablite

λ = 0.037

DPNF LP DL

0.48 0.47 0.45115mm Toplite GTI

0.46 0.45 0.44125mm Toplite GTI

140mm Toplite GTI





100mm Hemelite

140mm Hemelite

100mm Lignacite

140mm Lignacite

100mm Topcrete

140mm Topcrete

Table 1.9a: Cavity wall partial fill – 103mm brick • 50mm residual clear cavity • insulation • block • finish





Notes• Rendered blockwork maybe used as an alternative to facing brick. The U valueswill be equivalent or betterthan the values shown.• – Denotes U valuesexceeding 0.70W/m2K

11



DPNF

30mm Rockwoolλ = 0.033


0.39 0.38 0.37 0.37 0.35 0.34 0.33 0.33 0.32

0.38 0.37 0.36 0.36 0.34 0.33 0.32 0.32 0.31

0.40 0.39 0.38 0.36 0.35 0.35 0.34 0.33 0.32 0.31 0.31 0.30

0.50 0.49 0.48 0.45 0.43 0.43 0.42 0.40 0.38 0.38 0.37 0.35

0.45 0.44 0.43 0.41 0.39 0.39 0.38 0.36 0.35 0.35 0.34 0.33

0.53 0.52 0.51 0.48 0.46 0.45 0.44 0.42 0.40 0.40 0.39 0.37

0.48 0.47 0.46 0.44 0.42 0.41 0.41 0.39 0.37 0.37 0.36 0.35

0.63 0.63 0.61 0.56 0.53 0.53 0.51 0.48 0.45 0.45 0.44 0.42

0.60 0.60 0.58 0.54 0.51 0.51 0.50 0.47 0.44 0.44 0.43 0.41

0.64 0.63 0.61 0.56 0.53 0.53 0.51 0.48 0.46 0.45 0.44 0.42

0.61 0.60 0.58 0.54 0.52 0.51 0.50 0.47 0.44 0.44 0.43 0.41

0.67 0.66 0.64 0.60 0.56 0.55 0.54 0.51 0.47 0.47 0.46 0.44

0. 65 0.65 0.63 0.58 0.54 0.54 0.53 0.50 0.47 0.46 0.45 0.43

LP DL DPNF LP DL


DPNF LP DL

0.43 0.42 0.41115mm Toplite GTI

0.41 0.41 0.40125mm Toplite GTI

140mm Toplite GTI





100mm Hemelite

140mm Hemelite

100mm Lignacite

140mm Lignacite

100mm Topcrete

140mm Topcrete


DPNF

25mm Wallmate CW

λ = 0.025

30mm Wallmate CW

λ = 0.025

0.38 0.38 0.37 0.37 0.35 0.33 0.33 0.32 0.31

0.37 0.37 0.36 0.36 0.34 0.32 0.32 0.31 0.30

0.38 0.38 0.37 0.35 0.35 0.35 0.34 0.33 0.31 0.31 0.30 0.29

0.48 0.47 0.46 0.43 0.43 0.43 0.42 0.40 0.37 0.36 0.36 0.34

0.43 0.42 0.41 0.39 0.39 0.39 0.38 0.36 0.34 0.34 0.33 0.32

0.51 0.50 0.49 0.46 0.46 0.45 0.44 0.42 0.39 0.38 0.38 0.36

0.46 0.45 0.44 0.42 0.42 0.42 0.41 0.39 0.36 0.36 0.35 0.34

0.60 0.59 0.57 0.54 0.53 0.53 0.52 0.49 0.44 0.44 0.43 0.41

0.57 0.57 0.55 0.52 0.51 0.51 0.50 0.47 0.43 0.42 0.41 0.40

0.60 0.59 0.57 0.54 0.54 0.53 0.52 0.49 0.44 0.44 0.43 0.41

0.58 0.57 0.55 0.52 0.52 0.51 0.50 0.47 0.43 0.42 0.41 0.40

0.63 0.63 0.61 0.56 0.56 0.56 0.54 0.51 0.46 0.45 0.44 0.42

0. 61 0.61 0.59 0.55 0.55 0.54 0.53 0.50 0.45 0.45 0.44 0.41

LP DL DPNF LP DL

40mm Wallmate CW

λ = 0.025

DPNF LP DL

0.41 0.41 0.40115mm Toplite GTI

0.40 0.39 0.38125mm Toplite GTI

140mm Toplite GTI





100mm Hemelite

140mm Hemelite

100mm Lignacite

Table 1.9c: Cavity wall partial fill – 103mm brick • 50mm residual clear cavity • insulation • block • finish

140mm Lignacite

100mm Topcrete

140mm Topcrete

Table 1.9b: Cavity wall partial fill – 103mm brick • 50mm residual clear cavity • insulation • block • finish





12



DPNF

17mm Celotex CW2000

λ = 0.019

25mm Celotex CW2000

λ = 0.019

0.37 0.34 0.34 0.33 0.32 0.32 0.31 0.31 0.30

0.36 0.33 0.33 0.32 0.31 0.31 0.31 0.30 0.29

0.37 0.37 0.36 0.34 0.32 0.32 0.31 0.30 0.30 0.30 0.29 0.28

0.46 0.45 0.44 0.42 0.38 0.38 0.37 0.36 0.35 0.35 0.34 0.33

0.41 0.41 0.40 0.38 0.35 0.35 0.34 0.33 0.33 0.32 0.32 0.31

0.49 0.48 0.47 0.44 0.40 0.40 0.39 0.37 0.37 0.37 0.36 0.35

0.45 0.44 0.43 0.41 0.37 0.37 0.36 0.35 0.35 0.34 0.34 0.32

0.57 0.57 0.56 0.52 0.46 0.46 0.45 0.43 0.42 0.42 0.41 0.39

0.55 0.55 0.53 0.50 0.45 0.44 0.43 0.41 0.41 0.41 0.40 0.38

0.58 0.57 0.56 0.52 0.47 0.46 0.45 0.43 0.42 0.42 0.41 0.39

0.56 0.55 0.53 0.50 0.45 0.44 0.43 0.41 0.41 0.41 0.40 0.38

0.61 0.60 0.58 0.55 0.48 0.48 0.47 0.44 0.44 0.43 0.43 0.40

0.59 0.59 0.57 0.53 0.47 0.47 0.46 0.43 0.43 0.43 0.42 0.40

LP DL DPNF LP DL

29mm Celotex CW2000

λ = 0.019

DPNF LP DL

0.40 0.40 0.39115mm Toplite GTI

0.39 0.38 0.37125mm Toplite GTI

140mm Toplite GTI





100mm Hemelite

140mm Hemelite

100mm Lignacite

Table 1.9d: Cavity wall partial fill – 103mm brick • 50mm residual clear cavity • insulation • block • finish

140mm Lignacite

100mm Topcrete

140mm Topcrete

U Values (W/m2K) Insulation

& Surface Finish

DPNF

25mm Jablite

0.37 0.35

0.36 0.33

0.37 0.37 0.36 0.35 0.32

0.36 0.35 0.35 0.33 0.31

0.35 0.34 0.34 0.32 0.30

0.44 0.43 0.43 0.40 0.38

0.40 0.39 0.38 0.37 0.34

0.39 0.38 0.38 0.36 0.34

0.47 0.46 0.45 0.43 0.39

0.42 0.42 0.41 0.39 0.36

0.42 0.41 0.40 0.38 0.36

LP DL DU

0.40 0.40 0.39100mm Toplite GTI

0.38 0.38 0.37115mm Toplite GTI

125mm Toplite GTI

140mm Toplite GTI

150mm Toplite GTI








• DP – 13mm Dense plaster• LP – 13mm Lightweight plaster• DL – Drylining on dabs

(9.5mm plasterboard)• DU – Duplex plasterboard

(9.5mm plasterboard)*

Table 1.9e: Cavity wall partial fill – 16mm render • 100mm Toplite Standard

• 50mm residual clear cavity • 25mm Jablite • block • finish

Notes *foil faced Duplex plasterboard on 25mm thick x 38mm wide vertical battens at 400mm horizontal centres

13



& Surface Finish

DPNF

25mm Wallmate CW

0.38 0.35

0.36 0.34

0.38 0.38 0.37 0.35 0.33

0.36 0.36 0.35 0.34 0.32

0.35 0.35 0.34 0.33 0.31

0.45 0.45 0.44 0.41 0.38

0.41 0.40 0.40 0.38 0.35

0.40 0.39 0.39 0.37 0.34

0.48 0.47 0.46 0.44 0.40

0.44 0.43 0.42 0.40 0.37

0.43 0.42 0.41 0.40 0.37

LP DL DU

0.41 0.41 0.40100mm Toplite GTI

0.39 0.39 0.38115mm Toplite GTI

125mm Toplite GTI

140mm Toplite GTI

150mm Toplite GTI







Table 1.9f: Cavity wall partial fill – 16mm render • 100mm Hemelite Standard • 50mm residual

clear cavity • 25mm Wallmate CW • block • finish






U Values (W/m2K)

Toptherm Super blocks

Grade

Hemelite Standard

Topcrete Standard

DP

0.44

LP

0.42

DL

0.39

0.42 0.41 0.38

0.45 0.43 0.40

0.44 0.41 0.40

135

175

135

175

103mm facing brick outer leaf

& internal finish of

100mm Hemelite blockouter leaf with 16mm

render & internal finish of

Thickness(mm)

Table 1.10a: Cavity wall Toptherm Super – plastered or drylined finish

DP

0.42

LP

0.40

DL

0.38

0.40 0.39 0.36

0.43 0.41 0.39

0.42 0.40 0.38

14


U Values (W/m2K)

Toptherm Super blocks

Grade

Hemelite Paint Quality

Topcrete Paint Quality

135 0.45 0.43

0.45 0.41

0.46 0.44

0.44 0.42

175

135

175

Lignacite Fair Face0.45 0.43

0.43 0.41

135

175

103mm facing brick outer leaf

& internal paint or fair-face finish

100mm Hemelite block with 16mmrender outer leaf

& internal paint or fair-face finish

Thickness(mm)

Table 1.10b: Cavity wall Toptherm Super – direct paint or fair-face

U Values (W/m2K) Surface Finish

LPDP

0.55 0.31

0.52 0.30

0.68 0.66 0.60 0.50 0.29

0.64 0.62 0.56 0.47 0.28

0.61 0.59 0.54 0.46 0.28

– – – 0.63 0.34

– – 0.66 0.55 0.31

– 0.70 0.64 0.53 0.30

– – – 0.68 0.35

– – – 0.60 0.33

– – – 0.58 0.32

– – – – 0.40

– – – –– – –– ––

– – – –

– – – –

– – – –

– – – –

– – – –

– – – –

– – – –

0.38

0.38

0.40

0.39

0.38

0.41

0.40

0.40

DL TB1 TB3

– – 0.68100mm Toplite GTI

– 0.69 0.63115mm Toplite GTI

125mm Toplite GTI

140mm Toplite GTI

150mm Toplite GTI







100mm Hemelite

140mm Hemelite

150mm Hemelite

100mm Lignacite

140mm Lignacite

150mm Lignacite

100mm Topcrete

140mm Topcrete

150mm Topcrete

Table 1.11: Cavity wall clear cavity – 103mm facing brick • 50mm clear cavity • block • finish

Key to tables • DP – 13mm Dense plaster

• LP – 13mm Lightweight plaster• DL – Drylining on dabs


(9.5mm plasterboard)*• TB1 – 22mm Gyproc

Thermal board LD• TB2 – 35mm Gyproc

Thermal board Plus• TB3 – 40mm Gyproc

Thermal board Super


A 10mm airspace is assumed behind plasterboard and plasterboard laminates

Notes – Denotes U values exceeding 0.70W/m2K

15



100mm Hemelite Paint Quality

140mm Hemelite Paint Quality

100mm Lignacite Fair Face

140mm Lignacite Fair Face

100mm Topcrete Paint Quality

140mm Topcrete Paint Quality

Table 1.12: Cavity wall profile sheet steel cladding –50mm residual clear cavity • insulation • block • no finish

50mm Wallmate CW

0.40

33mm Celotex CW2033

0.45

0.39 0.43

0.40 0.45

0.39 0.44

0.41 0.47 (0.41)*

0.41 0.46 (0.41)*

Notes *Bracketed figures are for 38mm Celotex and assume a ventilated cavity.


LPDP

0.48 0.45 0.34 0.27

0.46 0.44 0.34 0.27

0.56 0.53 0.49 0.44 0.42 0.32 0.26

– – 0.66 0.58 0.54 0.40 0.31

– 0.70 0.64 0.56 0.52 0.39 0.30

0.69 0.66 0.60 0.53 0.50 0.38 0.29

– – – 0.66 0.61 0.44 0.33

– – – 0.64 0.60 0.43 0.33

– – 0.70 0.61 0.57 0.42 0.32

– – – – –

– – – – –

– – – – –

– – – – –

– – – – –

– – – – –

0.59 0.41

0.58 0.41

0.60 0.42

0.58 0.41

0.65 0.44

0.65 0.44

DL DU TB1 TB2 TB3

0.61 0.59 0.54190mm Toplite GTI

0.59 0.56 0.52200mm Toplite GTI

215mm Toplite GTI







190mm Hemelite

215mm Hemelite

190mm Lignacite

215mm Lignacite

190mm Topcrete

215mm Topcrete

Table 1.13: Solid wall – 16mm render • solid block • finish

Notes – Denotes U values exceeding 0.70W/m2K

16



115mm Toplite GTI

125mm Toplite GTI

150mm Toplite GTI

190mm Toplite GTI

Table 1.14a: Solid wall semi-exposed – Toplite GTI • finish

22mm GyprocThermal board LD

0.59

12.5mm foil-backed

plasterboard on 25mm

timber battens

– –

0.57 0.60 –

0.51 0.54 0.60

0.44 0.46 0.51

12.5mmplasterboard

on 25mmtimber battens

–

–

–

0.60

13mm Dense Plaster

–

–

–

0.57

13mm Lightweight

Plaster

Notes Plasterboard laminate of equivalent performance may be used.

U-Values(W/m2K)

Surface Finish

100mm Hemelite Standard

100mm Topcrete Standard

Table 1.14c: Solid wall semi-exposed –Hemelite/Topcrete • finish

30mm GyprocThermal board

Super on 25mmtimber battens

0.56

0.59

Notes Plasterboard laminate of equivalentperformance may be used.





Table 1.14b: Solid wall semi-exposed – Toplite Standard • finish

27mm GyprocThermal

Board Plus

0.59

30mm GyprocThermal Board LD

– –

0.50 0.54 –

0.42 0.45 0.59

Notes Plasterboard laminate of equivalent performance may be used.

9.5mmplasterboard






1.7 Floor solutionsTable 1.15 shows U values for beam

and block suspended ground floors

with different infill blocks.

The table also shows the improved

performance which can be obtained

by using Toplite Foundation blocks

as edge insulation at the perimeter

of the floor.

17


Ratio of P/A

0.20

Toplite

Hemelite

Topcrete

0.33

0.36

0.36

0.27

0.29

0.30

0.25

0.28

0.29

0.22

0.24

0.24

0.22

0.24

0.24

0.19

0.20

0.21

WithoutFoundation

block

WithFoundation

block

50mm screed

WithoutFoundation

block

WithFoundation

block

18mm Chipboard and 25mm Jablite

WithoutFoundation

block

WithFoundation

block


Infill blocktype

Table 1.15: Ground floor U values

0.25

Toplite

Hemelite

Topcrete

0.39

0.43

0.44

0.32

0.35

0.36

0.29

0.32

0.33

0.25

0.27

0.28

0.24

0.26

0.27

0.21

0.23

0.24

0.30

Toplite

Hemelite

Topcrete

0.44

0.49

0.51

0.36

0.39

0.40

0.32

0.35

0.36

0.27

0.30

0.31

0.26

0.29

0.29

0.23

0.25

0.25

0.35

Toplite

Hemelite

Topcrete

0.44

0.55

0.57

0.37

0.44

0.45

0.34

0.38

0.40

0.29

0.33

0.34

0.27

0.31

0.31

0.24

0.27

0.27

0.40

Toplite

Hemelite

Topcrete

0.53

0.61

0.64

0.43

0.48

0.50

0.36

0.41

0.43

0.31

0.35

0.36

0.29

0.32

0.33

0.25

0.28

0.29

0.45

Toplite

Hemelite

Topcrete

0.57

0.67

0.70

0.46

0.52

0.54

0.38

0.44

0.46

0.32

0.37

0.38

0.30

0.34

0.35

0.26

0.30

0.30

0.50

Toplite

Hemelite

Topcrete

0.62

0.73

0.77

0.50

0.57

0.59

0.40

0.47

0.48

0.34

0.39

0.41

0.31

0.35

0.36

0.28

0.31

0.32

0.55

Toplite

Hemelite

Topcrete

0.65

0.78

0.83

0.52

0.60

0.63

0.41

0.48

0.50

0.35

0.41

0.42

0.32

0.37

0.38

0.28

0.32

0.33

0.60

Toplite

Hemelite

Topcrete

0.68

0.82

0.87

0.54

0.62

0.65

0.42

0.50

0.52

0.36

0.42

0.43

0.32

0.37

0.39

0.29

0.33

0.34

Notes • The U values have been calculated in accordance with BRE Information Paper IP7/93.• Floor beams assumed at 515mm centres.• Foundation blocks are Toplite and taken as 275mm thick to a depth of 675mm below ground floor level. U values for

alternative thicknesses and depth available on request.• Uninsulated cavity walls below damp-proof course are assumed when foundation blocks are not used.

1.7.1 Example calculation

From the table determine the

U value of the beam and block

ground floor shown, using Hemelite

infill blocks, finished with 25mm

Jablite and 18mm chipboard, with

Toplite Foundation blocks as

edge insulation.

Solution

18


(i) Calculate the floor perimeter, P: P = 10+9+15+6+3+5 = 48m

(ii) Calculate the floor area, A: A = (6 x 5) + (10 x 9) = 120m2

(iii) Ratio of P/A P/A = 48/120 = 0.40

(iv) Find U value of insulated floor from table: P/A = 0.40, U value = 0.35W/m2K

10m

15m

9m

5m

3m

6m

Ratio of P/A

0.65

Toplite

Hemelite

Topcrete

0.71 0.57 0.43 0.37 0.33 0.30

0.87 0.66 0.52 0.44 0.38 0.34

0.93 0.69 0.54 0.45 0.40 0.35

0.74 0.58 0.44 0.38 0.34 0.30

0.91 0.68 0.53 0.44 0.39 0.34

0.97 0.71 0.56 0.46 0.41 0.35

0.77 0.60 0.45 0.39 0.34 0.30

0.95 0.70 0.55 0.45 0.40 0.35

1.02 0.74 0.57 0.47 0.41 0.36

0.79 0.62 0.46 0.40 0.35 0.31

0.99 0.73 0.56 0.47 0.41 0.35

1.06 0.77 0.58 0.48 0.42 0.36

0.81 0.62 0.47 0.40 0.35 0.31

1.02 0.74 0.57 0.47 0.41 0.36

1.10 0.78 0.60 0.49 0.43 0.37

0.83 0.63 0.47 0.40 0.36 0.31

1.05 0.75 0.58 0.47 0.42 0.36

1.13 0.79 0.61 0.49 0.43 0.37

0.85 0.65 0.48 0.41 0.36 0.32

1.08 0.77 0.59 0.48 0.42 0.36

1.17 0.81 0.62 0.50 0.44 0.37

0.86 0.65 0.48 0.41 0.36 0.32

1.10 0.77 0.59 0.48 0.42 0.36

1.19 0.81 0.62 0.50 0.44 0.37

Withoutfoundation

block

Withfoundation

block

50mm screed

Withoutfoundation

block

Withfoundation

block


Withoutfoundation

block

Withfoundation

block


Infill blocktype

0.70

Toplite

Hemelite

Topcrete

0.75

Toplite

Hemelite

Topcrete

0.80

Toplite

Hemelite

Topcrete

0.85

Toplite

Hemelite

Topcrete

0.90

Toplite

Hemelite

Topcrete

0.95

Toplite

Hemelite

Topcrete

1.00

Toplite

Hemelite

Topcrete

Table 1.15: Ground floor U values

Notes • The U values have been calculated in accordance with BRE Information Paper IP7/93.• Floor beams assumed at 515mm centres.• Foundation blocks are Toplite and taken as 275mm thick to a depth of 675mm below ground floor level. U values for

alternative thicknesses and depth available on request.

2.1 IntroductionAcoustic design generally involves

introducing measures to:

• control the level of sound in

particular parts of a building;

• limit the transmission of

unwanted noise.

The objectives can be obtained

through a combination of careful

consideration of building layout

(see section 2.2) and the

specification of building fabric

with the appropriate acoustic

performance.

Fabric performance is affected by

two important criteria. Sound

insulation is usually the main

consideration and in some cases is

covered by building regulations

(see section 2.3). Sound absorption

is the key consideration where the

control of reflected sound is

essential, for example in theatres

or concert halls (see section 2.4).

Concrete blockwork has long been

recognised to combine good

acoustic performance with

structural, thermal and fire resisting

properties. The use of Topblock

products enables the acoustic

requirements of many situations

to be met in a practical and cost

effective manner.

2.2 Internal layoutWhere possible arrange the internal

layout of a building to separate

noisy and quiet areas. The distance

between those areas can be

increased by forming ‘buffer zones’

from rooms such as kitchens, store

rooms and corridors, which do not

have critical levels of sound

transmission.

As the amount of sound transmitted

through a wall is related to its area,

consider minimising the shared wall

area between critical rooms by

adopting alternative shapes and

orientations. Introducing steps

and/or staggers can also help

reduce the shared wall area.

CIRIA report 127 ‘Sound control

for homes’ includes typical

measures which can be

advantageous.

2.3 Sound insulation2.3.1 Separating (party) walls

2.3.1.1 Regulations

Building Regulation E1 (England

and Wales) stipulate separating

walls between dwellings or between

dwellings and other parts of

buildings must resist the direct

transmission of airborne sound.

Guidance on meeting those

requirements is contained in

Approved Document E

(England and Wales).

In each case there are three

methods of demonstrating

compliance:

• Adopt one of the separating wall

constructions given in the

guidance documents, observing

the specifications for flanking wall

constructions.

• Demonstrate by testing of actual

walls or prototypes that the

specified levels of sound insulation

have been achieved or can be

achieved by a similar method

of construction.

• Provide a recognised technical

approval for the proposed

construction, for example an

Agrément Certificate.

19


2. Acoustic performance

The elements adjoining or ‘flanking’

the separating wall form indirect

paths for noise transmission and

may be critical to the overall level

of sound insulation provided.

Relevant guidance on flanking

wall construction is given in

Approved Document E.

2.3.1.2 Requirements

Table 2.1 shows the Topblock

solutions for separating walls, the

approval route employed and

any additional requirements for

flanking walls. Table 2.2 gives

guidance on the requirements

for flanking walls.

Unless a prescriptive

construction from building

regulations is being specified we

recommend approval for the

chosen separating and flanking

wall construction is obtained

before building work starts.

Topblock’s Technical Services

Department can advise on the

suitability of constructions not

featured in the tables.

20


Solid wall – plastered

215mm Topcrete Standardsolid (100mm blocks laid flatis the preferred solution)

Approval route

*AD-E (Type 1B)1 or 2 with A&Bor 3 with A,B&C

Flanking wall options from table 2.2

Table 2.1: Recommended separating wall solutions

Solid wall – drylined

215mm Toplite Standard or Toplite ‘7’

BBA Cert. No. 97/3324 1, 2 or 3 with A&B

195mm Topcrete SPW

215mm Topcrete Standardsolid (100mm blocks laid flatis the preferred solution)

AD-E (Type 1D) 1 or 2 with A&Bor 3 with A,B&C

195mm Topcrete SPW

Cavity wall – plastered

2 × 100mm TopcreteStandard solid. 50mm cavity

AD-E (Type 2B)

1, 2 or 3 with A&B

Cavity wall – drylined

2 × 100mm TopliteStandard or ‘7’. 75mm cavity

BBA Cert. No. 97/3324

2 × 100mm HemeliteStandard solid. 75mm cavity

AD-E (Type 2C)


AD-E (Type 1D) 1, 2 or 3 with A&B

Additional constructions for use when dwellings are stepped or staggered by at least 300mm (plastered or drylined)


AD-E (Type 2D)2 × 100mm HemeliteStandard solid or cellular. 75mm cavity

1, 2 or 3 with A&B

Notes For solutions in Scotland please consult Topblock Technical Services.*AD-E – Approved Document E.

2.3.1.3 Design and

workmanship

The performance of separating

walls should be ensured by

observing the following points:

• Fully fill all vertical and horizontal

joints with mortar.

• Connect the leaves of cavity

separating walls with the

minimum number of butterfly

pattern ties1 required for structural

integrity. Maintain the cavity to

the underside of the roof covering.

• Fill the joint between the

separating wall and the roof:

the method used for fire stopping

is suitable.

• Use joist hangers where joists

are supported by Toplite

separating walls.

• Where the flanking wall

construction includes a cavity

ensure a flexible cavity closer is

both specified and installed.

• Wherever possible avoid placing

electrical and television sockets on

the separating wall. Otherwise

ensure there is at least one block

length between sockets on

opposite sides of the wall.

• Wherever possible avoid

penetration of the wall by

structural members and services.

Where this is not possible, carry

out full sealing during

construction.

2.3.2 Other walls,partitions and floors

There is often a design requirement

to provide good levels of noise

control within those parts of

buildings which are not covered by

building regulations: the acoustic

performance of walls, partitions and

floors should be considered in any

specification. Particular attention

should be given to walls between:

• offices and production areas

in factories;

• bedrooms and public areas

in hotels;

• bedrooms/living rooms and

kitchens/bathrooms in dwellings.

A.Flanking wall bonded or tied to separating wall.

B. Cavity stopped with flexible closer (unless cavity is fully filled with a suitable insulant).

C. External walls should have openings on both sides of separating walls at all storeys which are at least 1m high and no more than 700mm from face of the separating wall.

3

21


Additional requirementsOption Flanking leaf Approval

1

Leaf of block of minimum120kg/m2

• 90mm Hemelite or Topcrete Standard solid

• 100mm Hemelite or Topcrete Standard cellular

AD-E

2Leaf of block less than 120kg/m2

• 100mm Toplite Standard or ‘7’

BBA Cert. No.97/3324

Leaf of block less than120kg/m2

• 100mm Toplite GTI with plaster finish

• 115mm Toplite GTI with drylined finish

BBA Cert. No.97/3323

Table 2.2: Flanking wall options

1 Equivalent ties which can be shown not to reduce sound insulation performance may also be specified.

Cavity stopped withflexible closer

Figure 2.1 Junction of separating and flanking walls

Notes *A ‘quiet’ room for either study or noisy activities is now frequently regarded as a desirable feature for many dwelling types.

2.3.2.1 Specification

requirements

The required level of noise control

will depend upon:

• the type of building;

• the mix of uses;

• any local planning requirements

for controlling transmission of

noise whether from outside to

inside or inside to outside.

Noise control requirements are

usually specified in terms of the

Weighted Sound Reduction Index

(Rw), which represents the airborne

sound insulation performance of a

building element, or the Weighted

Standardised Level Difference

(DnT,w) as defined in BS 5821.

Both are expressed in decibels.

Table 2.3 shows suggested Topblock

solutions for constructions to meet

the minimum performance

recommendations for walls and

floors given in CIRIA Report 127

‘Sound control for homes’; further

examples may be found in

BS 8233. Table 2.4 gives a selection

of Rw values for a range of

Topblock products.

Typical solutions

22


Situation MinimumDnT,w (dB)

Walls around a ‘quiet room’* 48

Minimum 100mm Topcrete, 140mm Hemelite or150mm Toplite Standard or Toplite ’7’, plastered or drylined.

Walls aroundother domesticrooms

38 Minimum 75mm block wall, plastered or drylined.

Floors aboveor below a‘quiet room’

46 Beam and block floor incorporating 100mmTopcrete or Hemelite blocks with screed finish.

Floors above orbelow otherdomestic rooms

38 Beam and block floor incorporating 100mmTopcrete or Hemelite blocks with screed finish.

Table 2.3: Suggested minimum airborne sound insulation performance of walls and floors


Table 2.4a: Sound reduction values, Hemelite

Finish

Weighted sound reduction index, Rw (dB)

75mm solid

90mm solid

No finish

42

100mm solid

140mm solid

150mm solid

190mm solid

200mm solid

215mm solid

100mm cellular

140mm cellular or hollow

190mm cellular

Notes • Finishes to wall are assumed to be applied to both faces.• The performance values of walls with finishes is applicable to Standard grade

and Paint Quality blocks. The performance of walls with no finish assumes the use of Paint Quality blocks.

43 44 44

Single leaf wall

44 44 46 45

45 45 47 45

47 48 49 48

48 49 49 49

50 51 51 51

50 51 51 51

52 52 52 52

43 44 45 46

45 46 47 46

48 49 49 49

Lightweight plaster

Dense plaster Drylining

Table 2.4b: Sound reduction values, Topcrete

Finish


75mm solid

90mm solid

No finish

44

100mm solid

140mm solid

150mm solid

190mm solid

215mm solid

100mm cellular

140mm cellular or hollow

215mm hollow

Notes • Finishes to walls are assumed to be applied to both faces.• The performance values of walls with finishes is applicable to Standard grade

and Paint Quality blocks. The performance of walls with no finish assumes the use of Paint Quality blocks.

46 47 47

Single leaf wall

46 47 48 48

47 48 49 48

50 51 52 51

51 52 52 52

53 54 54 54

54 55 55 55

45 46 47 46

46 51 52 51

50 53 54 53

Lightweight plaster

Dense plaster Drylining

23

24


Weighted soundreduction index, Rw (dB)

100mm thick

140mm thick

47

Notes • The performance of walls not featured is available on request.

Topcrete Fair Face

Lignacite Fair Face

50

100mm thick

140mm thick

47

50

Weathered Masonry

100mm thick

140mm thick

47

50

Table 2.4c: Sound reduction values, Toplite


Finish

100mm GTI

140mm GTI

No finish

37

190mm GTI

215mm GTI

100mm Standard

140mm Standard

190mm Standard

215mm Standard

100mm ‘7’

140mm ‘7’

190mm ’7’

215mm ‘7’

Notes • Finishes to walls are assumed to be applied to both faces.

41 43 43

Single leaf wall

42 44 46 45

45 47 48 47

47 48 49 48

40 43 45 45

44 46 48 47

48 49 50 49

49 50 51 50

42 44 45 45

46 47 48 47

49 50 50 49

50 51 51 50

Lightweight plaster

Denseplaster Drylining

Table 2.4d: Sound reduction values, Fair Face –solid blockwork walls without finishes

2.4 Sound absorption2.4.1 AbsorptionCoefficient

The degree of sound absorption

provided by a material is expressed

as an Absorption Coefficient for a

range of frequencies or a series of

octave bands, with a value between

0 and 1 (where 1 is perfect

absorption). The performance

required of a wall can be quoted in

terms of the Absorption Coefficient

once the use and layout of the

building have been considered.

2.4.2 Internal and external walls

Many rooms and enclosed areas,

such as theatres, concert halls,

cinemas and sports halls, require a

degree of sound absorption to

reduce unwanted echo effects

resulting from sound being

reflected from the walls.

Topblock has developed the

Echomaster range of blocks as a

cost effective route to sound

absorption without the need for an

additional absorbent finish.

Echomaster blocks incorporate a

pattern of slots and voids, which are

packed with mineral wool to extend

the sound absorption performance

across a wider range of frequencies.

Figure 2.2 shows the absorption

performance of Echomaster

blockwork between 100 and

5000Hz. The blocks provide a

robust surface and combine sound

absorption with good structural,

sound insulation, fire resistance and

aesthetic properties. Further details

are given in the Echomaster

brochure.

2.4.3 Noise barrier walls

Concrete blockwork barrier walls

can be very effective in controlling

external noise, particularly that

generated by roads and railways.

They have the additional benefit

of forming an attractive visual

screen. Many products from the

Topblock range are suitable for

this application.

The performance of noise barrier

walls can be improved by including

a degree of sound absorption; for

example, cellular blocks laid flat

with their voids exposed, provide

resonant absorption and offer an

attractive finish. They have proved

very effective in applications such

as underpass walls.

25


Figure 2.2 Comparison of the acoustic performance of Echomaster masonry against plain dense masonry

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

Ab

sorp

tio

n c

oeff

icie

nt

Frequency (Hz)

100 160 250

100mm Echomaster

140mm Echomaster

Plain dense masonry or plaster on solid background

400 630 1000 1600 2500 4000125 200 315 500 800 1250 2000 3150 5000

3.1 Design principlesBuilding Regulation A12 requires

buildings to be constructed so the

combined dead, imposed and wind

loads are sustained and transmitted

safely, without causing deflection

or deformation in any part of

the building.

Many masonry structures can be

designed to meet those

requirements by using prescriptive

rules in Building Regulations and

British Standards, without the need

for detailed structural calculations.

Those rules apply to:

• Houses and other small buildings

up to three storeys in height; see

Approved Document A3 (1992

edition) and BS 8103: Part 2: 1996

‘Code of practice for masonry

walls for housing’.

• Non-loadbearing partitions:

determination of thickness

according to panel length and

height is contained in BS 5628:

Part 3.

For structures outside the scope of

those rules, design methods are

contained in BS 5628: ‘Code of

practice for use of masonry’ which

consists of the following parts:

• Part 1: Structural use of

unreinforced masonry

• Part 2: Structural use of reinforced

and prestressed masonry

• Part 3: Materials and components,

design and workmanship

3.2 Unreinforcedwalls3.2.1 Characteristiccompressive strength of blockwork

The aspect ratio of a block –

the ratio of height to thickness –

affects the characteristic

compressive strength of the

blockwork masonry, termed fk.

The values for fk given in table 3.1a

and table 3.1b apply to Topblock

products laid in normal aspect.

Where blocks are laid flat, with a

unit aspect ratio between 0.4 and

0.5 – as for example, in party walls

– the fk values in table 3.2 should be

used. Consult table 3.3 for the fk

value of double-leaf collar jointed

walls. The fk value of Topcrete SPW

blockwork built using group (iii)

mortar is 6.0N/mm2.

26


3. Structural design

Table 3.1a: Characteristic compressive strength ofblockwork, fk , using solid blocks

Compressive strengthof unit (N/mm2)

Block thickness (mm)

75mm

2.8 3.5 7.0 10.0 15.0 20.0

– 3.5 6.4 – – –

3.5 6.4 8.2 (10.0) (11.6)

3.5 6.4 8.2 10.0 11.6

(3.3) (6.1) – – –

(3.1) 5.8 (7.4) (9.0) (10.4)

(3.1) (5.6) – – –

2.9 5.3 6.8 8.3 9.7

2.8 5.1 6.5 8.0 9.2

2.4 4.4 5.7 (6.9) (8.0)

2.3 4.3 (5.5) (6.7) (7.8)

2.2 4.1 5.3 (6.4) (7.4)

90mm –

100mm 2.8

115mm 2.7

125mm 2.5

130mm 2.5

140mm 2.3

150mm 2.2

190mm 1.9

200mm 1.9

215mm 1.8

Characteristic compressive strength, fk , (N/mm2)

2 For Scotland refer to Building Standards (Scotland) Regulation 113 For Scotland refer to the ‘Small Buildings Guide’ for compliance with Part C of the Technical Standards.

Notes • Blocks have a face size 440 x 215mm and are laid in normal aspect.• All values shown are for blockwork built with designation (iii)

mortar. Values for other blockwork built with mortar of other designations may be determined from BS 5628: Part 1.

• Values shown in brackets are not stock block products but can be made to order.

The compressive strength of cellular

or hollow blocks is based on their

gross area: no allowance need be

made for the voids. Where the

voids will be completely filled with

concrete in-situ the compressive

strength should be calculated on

the net area of the block, provided

the 28 day cube strength of the

infilling is not less than the

strength of the block.

27



Characteristic compressivestrength, fk , (N/mm2)

Mortar group

(i)

3.5 7.0 10.0 15.0 20.0

2.8 5.4 6.2 8.4 10.4

5.3 6.0 7.7 9.3

5.1 5.7 7.0 8.1

(ii) 2.8

(iii) 2.8

Table 3.1b: Characteristic compressive strength of blockwork, fk , using cellular or hollow blocks


Characteristiccompressive strength,

fk , (N/mm2)


100mm

3.5 7.0 10.0 15.0

3.5 5.4 (5.5) (5.7)

4.7 (5.0) (5.5)

(4.5) (4.9) (5.4)

4.0 (4.6) (5.3)

3.8 (4.5) (5.2)

140mm 2.9

150mm (2.8)

190mm 2.4

215mm 2.2

Table 3.2: Characteristic compressive strength of blockwork, fk , using solid blocks laid withaspect ratios between 0.4 and 0.5

Compressive strength of unit (N/mm2)

Characteristic compressivestrength, fk , (N/mm2)

Wall thickness(mm)

190

3.5 7.0 10.0 15.0 20.0

2.4 4.7 6.1 8.3 10.2

4.4 5.7 7.7 9.5

4.6 5.9 6.5 9.1

215 2.2

190

Mortar group

(i)

(ii)2.4

4.3 5.5 7.1 8.5215 2.2

4.4 5.7 6.9 8.0190(iii)

2.4

4.1 5.3 6.4 7.5215 2.2

Table 3.3: Characteristic compressive strength ofblockwork, fk , for collar jointed walls

Notes • Face size of units 440 × 215mm.• Values established by the Concrete Block Association.

Notes • Blocks have a face size 440 x 215mm and are laid in normal aspect.

• All values shown are for blockwork built with designation (iii) mortar. Values for other blockwork built with mortar of other designations may be determined from BS 5628: Part 1.

• Values shown in brackets are not stock blockproducts but can be made to order.

Notes • Values established by the Concrete Block Association.

3.2.2 Blockworkconstruction options

Laying blocks flat is an effective

way of constructing 190 – 215mm

wide solid walls with good strength

and sound insulation whilst keeping

the unit weight to a minimum.

There are three options:

• lay 440 × 215 × 100mm blocks flat

(aspect ratio 0.46) to construct

215mm wide masonry (see

figure 3.1 and table 3.2);

• use Topcrete SPW blocks (aspect

ratio 0.33) to construct 195mm

wide masonry (see figure 3.2);

• lay 390 × 190 × 100mm blocks flat

(aspect ratio 0.53) to construct

190mm walls (see figure 3.3).

The use of heavy units can also be

avoided by using a double-leaf

collar jointed wall. This is

particularly suited to constructing

190mm or 215mm wide walls with

both faces built fair (see figure

3.4 and table 3.3).

28


Figure 3.1 215mm wall constructed with 100mm thick blocks laid flat

Figure 3.3 190mm walls constructed with 100mm thick blocks laid flat Figure 3.4 Double-leaf collar jointed wall

215mm

440mm

100mm

195mm

440mm

65mm

190mm

390mm

100mm

Collar joint

Reinforcementor metal ties

Figure 3.2 195mm walls constructed using Topcrete SPW

Block thickness(mm)

3.2.3 Partial safety factors

Topblock products are

manufactured under an ISO 9002

quality assurance system and

conform to the ‘Special Category

of Manufacturing Control’

requirements specified in BS 5628:

Part 1. Consequently, the partial

safety factors for material

strength given in table 3.4 may

be employed.

3.2.4 Laterally loaded walls

Recommendations for walls subject

to lateral loading are given in

BS 5628: Part 1. Such loading

must be taken into account when

the lateral load is the predominant

one and when the wall must

be designed to resist

accidental damage.

The flexural strength of blockwork,

fkx, is given in BS 5628: Part 1:

table 3 and relates broadly to the

compressive strength of the units

(water absorption is not a relevant

factor). The values apply to walls

built with solid, cellular and

hollow blocks.

Section properties of blockwork

are shown in table 3.5: when

calculating section properties no

account need be taken of the voids

in cellular and hollow units.

29


90mm

Section Modulus(Z), per metrelength (cm3/m)

1,350

1,667

2,604

3,267

3,750

6,017

6,667

7,704

100mm

125mm

140mm

150mm

190mm

200mm

215mm

Category of construction control

Partial safety factor(γm)

Special Normal

2.5 3.1

Table 3.4: Partial safety factors using Topblock products

Table 3.5: Section properties of blockwork

Height (m)

3.2.5 Non-loadbearinginternal walls

The limiting dimensions for

internal walls not required to

support imposed lateral or vertical

loading are given in BS 5628:

Part 3. Wall thickness is

determined by the length and

height of the panel and by the

nature and extent of any vertical

and/or horizontal restraint

provided (see tables

3.6 to 3.8).

It may be necessary to modify the

thickness to take account of:

• openings;

• fire resistance;

• sound insulation.

30


Table 3.6: Minimum block thickness – walls restrained at both ends


Length (m)

2.4

2.7

3.0

3.3

4.0

5.0

6.0

4 5 6 7 8 9 10 11 12

Height (m)

90 100 140 140 140 190 190 190 190

90 100 140 140 150 190 190 190 190

90 100 140 140 150 190 190 190 200

90 100 140 140 150 190 190 200 215

100 140 140 140 190 190 190 200 215

100 140 140 150 190 190 190 215 215

140 140 140 190 190 190 200 215 –

Table 3.7: Minimum block thickness – walls restrained at both ends and top


Length (m)

Height (m)

2.4

2.7

3.0

3.3

4.0

5.0

6.0

4 5 6 7 8 9 10 11 12

75 75 75 75 90 90 90 90 90

75 75 75 90 90 90 90 90 90

75 75 75 90 90 90 100 100 100

75 75 90 90 90 100 100 140 140

90 90 90 100 100 140 140 140 140

100 100 140 140 140 140 140 140 140

100 100 140 140 140 140 140 150 150

Table 3.8: Minimum blockthickness – walls restrained at top only

Minimum blockthickness (mm)

2.2

2.7

3.0

4.2

4.5

5.7

6.0

6.4

75

90

100

140

150

190

200

215

3.3 Reinforced wallsAdding reinforcement to blockwork

improves both the vertical

loadbearing capacity and the

bending resistance of the masonry.

Reinforced blockwork should be

constructed in accordance with the

recommendations of BS 5628:

Part 2. Further guidance for

reinforced free-standing walls is

given in BRE Good Building Guide

(GBG) 19, and for reinforced

retaining walls in GBG 27.

There are two common methods of

forming reinforced blockwork:

• placing reinforcement and

concrete in the cores of hollow

blocks (see figure 3.5).

• placing reinforcement and

concrete in the cavity between

two leaves of blockwork: this

construction is known as grouted-

cavity masonry (see figure 3.6).

Mortar mixes for reinforced

blockwork should be designation (i)

or (ii) according to BS 5628: Part 2.

However, designation (iii) mixes

may be used if the lateral load

resistance is enhanced by bed

joint reinforcement.

Concrete infill should be a

minimum of grade 25 as described

in BS 5328; alternatively the

following volume proportions

may be used: 1:1/4:3:2

cement:lime:sand:aggregate using

aggregate not greater than 10mm.

3.3.1 Cover toreinforcement

When determining fire resistance

the block may be considered as

forming part of the cover to the

reinforcement, in accordance with

BS 8110: Part 2. However, when the

durability of the reinforcement is

being assessed only the thickness of

the concrete infill can be considered

as forming the cover to the

reinforcement (see figure 3.7).

The minimum concrete cover

required for durability under a

range of exposure conditions is

given in BS 5628: Part 2: Table 14.

31


Figure 3.5 Reinforcement: hollow blockwork

Figure 3.6 Reinforcement:grouted-cavity masonry

Figure 3.7 Determination of coverfor fire resistance and durability

450mm

(1)

Concrete infill(2)

Notes (1) Thickness of cover for determination of fire resistance.(2) Thickness of cover for determination of durability.

3.4 Diaphragm wallsA diaphragm wall consists of two

parallel leaves of blockwork – each

usually 100mm thick – connected

with cross ribs of blockwork which

may be bonded or tied according to

the requirements of the design

(see figure 3.8).

Diaphragm walls are particularly

suitable to tall, single storey

buildings as they do not require a

separate structural frame. They can

be designed for high lateral and

vertical loading conditions and are

straightforward to construct,

providing the structure, cladding

and internal finish.

Diaphragm walls derive their

strength from the series of

connected boxes or I sections which

have high resistance to vertical and

horizontal loads: table 3.9 compares

the properties of a 440mm wide

diaphragm wall with conventional

cavity and solid walls. The section

modulus, and potentially

the lateral bending

strength, of walls of the

area shown in the table, is

over eight times that of a

250mm wide cavity wall.

The roof of a building

may be used to prop the

top of the external walls

and so keep wall thickness

to a minimum. Wind

loading can be transferred

into the roof structure by

using a reinforced

concrete capping beam.

For high lateral loads, such as those

occurring in retaining walls,

prestressing can be used to improve

the performance of the wall.

The wide cavity of a diaphragm

wall will easily accommodate a

post-tensioning system using

unbonded reinforcing bars.

Topblock products for the

construction of diaphragm walls

should be selected from the

relevant product brochures taking

into account the strength and

surface finish required. Fair Face

blocks can be used in both leaves

of a diaphragm wall.

Further details on the design of

concrete diaphragm blockwork

walls can be found in two design

guides which incorporate research

carried out at University of

Manchester Institute of Science

and Technology (UMIST):

• The Design of concrete blockwork

diaphragm walls;

• The Design of prestressed

concrete blockwork diaphragm

walls.

Copies of these guides are available

on request.

32


Table 3.9: Properties of cavity, solid and diaphragm walls

Type of wall Plan area(m2)

Length = 1300mm

0.260Cavity100

100

Sectionmodulus

(cm3)

4330

0.280 10000

0.284 35660

Figure 3.8 Diaphragm walls

Metal tie

Minimum 440mm

215

440Diaphragm

Solid block

4.1 The causes ofmovementAll buildings undergo small

movements and dimensional

changes from various causes;

those which most affect concrete

masonry are:

• changes in moisture content of the

blockwork (reversible);

• changes in temperature

(reversible);

• carbonation of the concrete

(non-reversible);

• movement of the adjoining

structure (reversible or

non-reversible);

There is a general tendency for

concrete masonry to contract as it

dries to equilibrium moisture

content and the concrete

carbonates. Clay masonry, by

contrast, expands as the masonry

matures and adsorbs water.

Unless proper provision is made to

allow such movements to take place

in a controlled manner, cracking

may occur: such cracking presents

little hazard, but can be unsightly.

The advice given here is based

upon the recommendations of

BS 5628: Part 3 and long-term

experience.

4.2 Provision formovementThe amount of movement to be

expected is related to the moisture

content of the materials, and the

ambient temperature during

construction. Longitudinal

movement in loadbearing masonry

is likely to be less than that in non-

loadbearing masonry because of the

restraint provided by the structure.

Whilst it is possible to calculate the

likely level of movement and then

to design for it, the number of

variables involved make calculation

complex; it is more usual to:-

• divide masonry into a series of

discrete panels, separated by joints

which allow movement of the

panels, and/or

• to restrict movement by using bed

joint reinforcement.

Internal walls in single occupancy

dwellings do not normally require

movement joints; any small

movement cracks are made good

after the building has dried out.

However, if the length of internal

walls exceeds three times their

height then provision for movement

may need to be considered.

4.2.1 Joints toaccommodate horizontalmovement

Movement joints should be

considered at the following

locations:

• at regular spacings in long runs

of walling;

• above and below openings;

• at changes in wall height;

• at changes in wall thickness;

33


4. Movement control

7.0 - 8.0

• at junctions with dissimilar

materials;

• to coincide with movement joints

in other parts of the construction.

Movement joint spacings for

Topblock products in walling are

given in table 4.1. Where end

restraint is provided, such as at

bonded corners, the recommended

spacings should be halved. Long,

low panels – those with length to

height ratios greater than 3:1 –

should have joints at reduced

spacings. In such cases, bed

reinforcement may be a

better solution as this will avoid

an excessive number of

movement joints.

4.2.2 Formation ofmovement joints

Joints to accommodate horizontal

movement should be straight,

10mm wide butt joints built in as

work proceeds and filled with

compressible filler (see figure 4.2).

Wider joints may be required where

they pass through the whole

structure. In some situations, for

example internal walls, a butt joint

may be used without filler.

Suitable joint fillers include flexible

cellular polyethylene, cellular

polyurethane or foam rubber.

Internal joints which generally only

need to allow for contraction, may

be filled with fibreboard or weak

mortar: the latter should be

confined to joints carried

through plasterwork.

Structural continuity across

movement joints, and at junctions

of masonry with the structural

frame, is achieved by using metal

ties with one end de-bonded (for

example by a plastic sleeve) in

alternate masonry bed joints

(see figure 4.3).

34


Table 4.1: Recommendedmovement joint spacings

Joint spacing(m)Product

Hemelite

Topcrete

Toplite

Lignacite

Weatheredmasonry

7.0 - 8.0

7.0 - 8.0

6.0

7.0

Figure 4.2 Typical movement joint

Flat tie to alternate courses

Jointfiller

Sealant whererequired

Figure 4.3 Movement jointwith flat-strip metal ties

Joint filler


Joints exposed directly to the

elements, such as those in fair-faced

work, should be finished with

suitable sealants such as one or

two part polysulphides. Sealants

can be obtained in colours

matching or contrasting with the

masonry, and should be installed in

accordance with the manufacturer’s

instructions regarding priming

and sealant depth.

Movement joints must be

continuous through applied rigid

finishes such as plaster or render

(see figure 4.4). The use of a

proprietary plaster/render stop

bead will give the best results,

although knifing through the

plaster may be an acceptable

alternative in some cases.

Further construction details for

movement joints are given in

figures 4.10 – 4.21.

4.2.3 Vertical and lateralmovement

In non-loadbearing walls a gap,

usually packed with soft filler, is left

at the soffit to allow for vertical

movement. Lateral restraint can be

provided by lengths of steel angle

fixed to the soffit on either side of

the masonry after the wall has been

constructed (see figure 4.5).

Alternatively, sliding ties may be

built into masonry perpend joints

and fixed to the soffit: the use of

ties which do not permit movement

may cause dislodgement of the

top course of masonry.

35


Figure 4.4 Movement joint continued through rigid finishes

Figure 4.5 Lateral restraintof non-loadbearing walls

Joint filler

Stop bead


Steel angleprovidinglateral support

Soft filler

Loadbearing masonry does not

generally require provision for

vertical movement. However,

thermal movements in concrete

roofs bearing directly onto

concrete masonry may produce

lateral pressure in the masonry:

the introduction of slip planes will

help prevent dislodgement of the

top course of blockwork

(see figure 4.6). Slip planes should

be formed with double layers of

polyethylene sheeting or damp

proof membrane material.

4.2.4 Bed jointreinforcement

Movement may also be controlled

using prefabricated wire

reinforcement in mortar bed joints

to distribute stresses throughout the

immediate area of the wall

(see figure 4.7). This will prevent

major cracking.

Bed joint reinforcement may

be used:

• at stress concentrations around

door and window openings

(see figure 4.8);

• in long panels where movement

joints are impractical

(see figure 4.9);

• to increase the spacing of

movement joints beyond

that recommended for

unreinforced masonry.

36


Figure 4.6 Slip planes

Figure 4.7 Bed joint reinforcement

Concrete roof deck

Slip planes Reinforcement

4.2.5 Mortar

A significant proportion of the

overall shrinkage of masonry is

due to the mortar. The effect of

the shrinkage can be reduced by

ensuring mortar joints are weaker

than the masonry units; this reduces

the stresses by allowing

redistribution of forces within the

wall. However, the mortar must still

be compatible with the strength

and durability requirements of

the masonry.

4.2.6 Sills and copings

Fractures in one-piece sills resulting

from building settlement may be

avoided by bedding the sill only

under the jambs and mullions,

leaving the intervening sections

clear. Those portions are then

pointed when the building has

undergone its initial settlement

and the mortar in the masonry

has matured.

Copings may require additional

provision for movement to allow

for the greater dimensional changes

produced by solar absorption.

4.2.7 Differentialmovement

Differential movement may occur

when designs combine materials

with differing physical

characteristics. This is not usually a

problem when various types of

concrete masonry are combined;

for example only a small amount

of differential movement will be

produced between a Topcrete

dense concrete outer leaf and

a Toplite inner leaf.

However, allowance must be made

for differential movement when

concrete and clay masonry are

used in adjoining leaves and the

use of rigid wall ties should be

avoided. When concrete and clay

units are built into the same panels,

slip planes and/or more closely

spaced movement joints may be

necessary to allow for the

differential movement.

4.2.8 Site practice

The risk of excessive movement

caused by drying shrinkage can be

reduced by protecting both stacked

blocks and partially complete work

from rain and snow. The tops of

stacked blocks should be protected

by waterproof sheeting. Blocks can

be supplied shrink-wrapped: once

packs have been opened the blocks

should be protected during adverse

weather. During very hot conditions

partially completed blockwork

should be protected from

rapid drying out.

37


Figure 4.8 Bed joint reinforcement at openings

Figure 4.9 Bed joint reinforcement in long panels

Bed joint reinforcement

Bed joint reinforcement

4.3 Summary

• Internal walls in single occupancy

dwellings do not normally require

movement joints.

• Movement joints in unreinforced

masonry should normally be

6.0 – 8.0m apart, for normal

storey height walls.

• Unrestrained or lightly loaded

walls with length/height ratios

greater than 3:1, such as low

horizontal panels or parapet walls,

need either frequent movement

joints or reinforcement.

• Use bed joint reinforcement to

control movement at stress

concentrations such as window

and door openings, or to extend

the spacing of movement joints.

• Allow for movement at the tops

of walls.

• Avoid mortars which are

too strong.

• Take care when mixing materials

of different compositions, such as

clay or concrete, in the same wall.

Introduce movement joints and

slip planes as appropriate.

38


Figure 4.11 Movement jointsat an intersecting wall

Sealant where required

Joint filler

300 x 25 x 3mm flat section metal tiewith one end de-bonded at 450mmvertical centres

6mm diameter metalrods with one endde-bonded

Figure 4.10aMovement jointsto wallsincorporatingsolid blocks

Joint filler (and sealantwhere required)

Flat metal tiewith one endde-bonded

Joint filler (andsealant whererequired)

Figure 4.10c Movementjoints to walls incorporatinghollow blocks

Figure 4.10b Movementjoints to walls incorporatinghollow blocks

Joint filler (and sealantwhere required)

Voids filled withstiff mortar tosupport tie

Flat metal tie with oneend de-bonded

39


Figure 4.12 Movement joint tothe inner leaf of a cavity wall

Figure 4.14 Movement joint to arendered outer leaf

225m

m M

AX

IMU

ME

MB

ED

ME

NT

MIN

IMU

M 1

00m

m

Figure 4.13 Movement joint at externalwall junction to separating wall

Wall ties at maximum300mm vertical centres



300 x 25 x 3mm flat section metaltie with one end de-bonded at450mm vertical centres

25mm x 3mm flatsection metal tie withboth ends de-bonded(length to suit) at450mm vertical centres



Sealant

Render stopbeads

25mm clear

225mm max

Outer leaf

Outer leaf

Inner leaf

225mm max

225mm max 225mm max

Joint filler

Joint filler

Joint filler

Figure 4.15 Movement joint to the side of door openings

Vertical movement jointcontinued up to top of wall Flat section metal tie

with one end de-bondedat 450mm vertical centres

Movement joint

Elevation

Joint filler

Lintel

Lintel bearing beddedand jointed on DPC ortwo layers of DPM

Render

40


Figure 4.17 Movement joint to blockworksupported by a steel frame


Flat section metal ties with de-bonding sleeves at 450mmvertical centres. Allow aminimum 100mm embedment.Ties fixed to column (eg shotfited).

Joint filler

Fire protectionto column

Column

225mm max.

40mm min.

Outer leaf

Figure 4.18 Movement joint to blockworksupported on a steel frame with internal pier

Joint filler

75mm min.

Figure 4.16 Movement joint toblockwork at internal steel column


Flexible ties at max.300mmverticalcentres

Fireprotectionto column

Joint filler

Column


Joint filler

Flexible ties at max.300mmverticalcentres

Topblockblocks

Topblockblocks

Topblockblocks

Topblockblocks

41


Sealantwhererequired

Weephole

Continuoussupportangle

Figure 4.19 Movement joint to blockworksupported on a steel frame

Cavitytray

Compressiblejoint filler

In-situ floor formedfrom compositesteel decking andreinforced concrete

Steel channel andcolumn (providefire protectionand thermalinsulation asrequired)

Topblock Fair Face

Sealant onsealant backer

Metal lathing weldedto bearing of supportangle to improvemortar bond



Weephole

Continuoussupportangle

Cavitytray

Reinforcedconcretefloor

Cast inanchor

Facingbrickwork

Figure 4.20 Movement joint with top restraintto blockwork supported on a concrete frame

Topblockblocks

Topblockblocks

Flat sectionmetal ties with de-bondingsleeves at450mm centres


42


Figure 4.21 Movement joint at reinforced concrete column


Joint filler

Dovetail channelcast into column

Concretecolumn

Concretecolumn

150 x 25 x 3mmFlat section metal tieswith de-bondingsleeves at 450mmvertical centres.

Concrete masonry is inherently

durable and able to resist aggressive

environmental conditions such as

frost and sulphate soils.

5.1 Frost resistanceConcrete masonry is resistant to

frost attack: when built fair, units

will experience little more than

slight surface weathering, provided

they have been selected on the

basis of the recommendations

of BS 5628: Part 3.

There is little or no risk of frost

attack when units are used:

• internally, above or below the

damp-proof course (dpc);

• externally, above dpc when

protected by cladding or render.

All products from the Topblock

range are suitable for use in those

positions: advice on the selection of

units for other applications is given

in table 5.1. Further guidance can

be found in BS 5628: Part 3, or

obtained from Topblock.

5.2 SulphateresistanceThe presence of sulphates in the

ground has a detrimental effect

upon concrete: when site trials

reveal more than modest levels of

sulphates there may be concern that

blocks will be susceptible to attack.

BRE Digest 363 ‘Sulphate and acid

resistance of concrete in the ground’

gives guidance on the specification

of in-situ and precast concretes

for such conditions and classifies

soils on the basis of the amount of

sulphates present, with 1 indicating

little or no sulphates and 5 high

sulphate content.

43


5. Durability

Table 5.1: Selection of units for frost resistance

Application

Recommendedproducts

Unprotectedwalls above

dpc

External walls belowdpc/ or nearground level

Parapets(unrendered)

Freestandingwalls with

copings

Freestandingwalls withcappings

Earthretaining

walls withcoping orcapping

HemeliteFoundation

Hemelite7.0N/mm2

Topcrete

Toplite Standard

TopliteFoundation

Toplite ’7’

Fair FaceRange

✓

✓

✓ – – – –

✓ ✓ ✓ ✓ ✓

✓ ✓ ✓ ✓ ✓ ✓

✓ ✓ ✓ ✓ ✓ ✓

✓ ✓ – – – –

✓ ✓ ✓ ✓ ✓ ✓

✓ ✓ ✓ ✓ ✓ ✓

In practice, blocks have been used

below ground in all kinds of

sulphate conditions for many years

before a potential problem with

sulphates was identified; there has

been no report of any failure.

Recent research4 supports the

long term empirical evidence

and suggests the guidance in BRE

Digest 363 is too conservative.

The research supports the BRE

view that carbonation imparts

sulphate resistance to concrete:

precast masonry units have a more

open texture than concrete cast

in-situ and are more readily

able to surface carbonate.

5.2.1 Specificationguidance

When specifying blocks for sites

where sulphates are present, always

determine whether:

• the conditions found relate to the

depth at which the concrete units

are to be used: very few sites have

sulphate concentrations greater

than class 1 in the first metre

of soil.

• ground water is likely to be

present at the depths at which

units are to be used: the risk of

sulphate attack in dry conditions

is minimal.

The following recommendations are

made on the basis of BRE Digest

363 and long-term research4.

Internally, above or below dpc:

no risk of sulphate attack.

Externally, above dpc, protected

by render or cladding: no risk of

sulphate attack.

Externally, above dpc and

unprotected by render or

cladding: levels of sulphates in the

atmosphere or precipitation are not

sufficient to present a risk of

sulphate attack for any

Topblock product.

Externally, below dpc: the

following units are suitable for use

in class 1, 2 and 3 sulphate

conditions:

• Hemelite Foundation

• Hemelite 7.0N/mm2

• Topcrete

• Toplite Standard

• Toplite Foundation

• Toplite 7

44


4 Sulphate resistance of aggregate concrete blocks: Pettit G. Harrison W. Littleton I. Proceedings of the 15th International Congress of the Precast Concrete Industry July 1996.

6.1 Regulations andguidanceIncreased awareness of Health and

Safety issues has focused attention

on building materials, including

consideration of manual handling.

The over-riding need is to ensure

a safe environment and good

working conditions for the

construction team.

Two items of legislation are relevant

to the manual handling of blocks:

• Manual Handling Operations

Regulations (1992), places duties

on employers to carry out a risk

assessment on all manual

handling tasks;

• Construction (Design and

Management) Regulations (1994),

imposes mandatory Health and

Safety requirements on clients,

designers and contractors.

Health and Safety Executive (HSE)

Construction Sheet 37 ‘Handling

Building Blocks’ gives guidance on

meeting the requirements of those

regulations. It advises there is a

high risk of injury in the single-

person repetitive handling of units

heavier than 20kg. Units heavier

than 20kg should be handled

mechanically or by two man teams.

Single-person handling of a small

number of heavier units – such as

quoins and reveal blocks – is not

identified as posing a high risk

of injury.

6.2 Safe handling ofblocks6.2.1 Designconsiderations

The majority of Topblock products,

including all 100mm thick units and

most 140mm solid units, fall within

the guidance for single-person

repetitive handling specified in

Construction Sheet 37. Unit weights

are given in tables in the relevant

product brochures.

Where the proposed walling

involves the use of blocks weighing

more than 20kg, there are two ways

to deal with the identified risk:

• Change the block specification.

You may be able to:

• select a lighter solid unit, or

• select a cellular or hollow unit

instead of a solid unit, without

compromising essential

requirements.

• Change the construction details.

Options for constructing walls from

75 to 215mm thickness are given in

tables 6.1 and 6.2. Solid walls 190

or 215mm thick may be formed in

one of two ways:

• if a finish is required to both faces,

lay blocks flat;

• if both faces are to be built fair,

lay 90 or 100mm units back to

back to form a collar jointed wall.

Using blocks in different aspect

ratios may affect the characteristic

compressive strength of the

blockwork (the fk value). Please

refer to section 3.2.1 for further

details of these constructions.

45


6. Block Handling

Toplite Foundation 3.5N/mm2

100mm Hemelite or Topcrete solid units

Block options

Block options

6.2.2 Site handling

6.2.2.1 Handling by crane

Do not lift packs of blocks over

the workforce when using

crane off-load vehicles and low

level cranes. Packs to be raised

by tower crane and high level

crane should be netted or

placed in cages

before lifting.

6.2.2.2 Packaging

Topblock offer a range of

packaging options to suit

individual site requirements:

• packs on pallets;

• packs with voids for fork-lift

handling (not available for

fair-faced or paint quality

products);

• packs for handling by grab.

46


Wall thickness

100mm Sound absorbing walls 100mm Echomaster

140mm

195mm

255mm

260mm

275mm

290mm

300mm

Sound absorbing walls

Separating walls

Solid foundations

Solid foundations

Solid foundations

Solid foundations

Solid foundations

140mm Echomaster

195mm Topcrete SPW

Hemelite Foundation



Hemelite Foundation

Construction options

Wall thickness

75mm 1 × 75mm single leaf Any 75mm block

100mm 1 × 100mm single leaf Any 100mm block

140mm 1 × 140mm single leaf

140mm Hemelite solid 3.5 or 7.0N/mm2

140mm Hemelite cellular or hollow

140mm Topcrete cellular or hollow

140mm Toplite GTI, Standard or ‘7’

140mm Lignacite solid

190mm Hemelite cellular or hollow


390 × 190 × 100mm Hemelite or Topcrete solid units

90mm Hemelite or Topcrete solid units

190mm

1 × 190mm single leaf

1 × 190mm single leaf, units laid flat

2 × 90mm leaves, collar jointed

215mm Hemelite hollow units


440 × 215 × 100mm Hemelite or Topcrete solid units

215mm

1 × 215mm single leaf

1 × 215mm single leaf, units laid flat

2 × 100mm leaves, collar jointed

Construction options

Table 6.1: Options for constructing blockwork walls

Table 6.2: Options for constructing walls for special requirements

6.2.3 Site practice

Always consider health and safety

matters during design and

construction stages and adopt

good working practices.

Observe the following points:

Site organisation:

• minimise manual handling by

delivering units as close to the

point of laying as safety

considerations permit.

• move blocks in packs and by

mechanical means wherever

possible.

• store blocks on a clean, level and

firm base.

• avoid stacking blocks above head

height, unless they are to be

moved by mechanical means.

• provide protective equipment –

including safety helmets, safety

footwear and suitable gloves –

and ensure it is used.

• ensure the blocklayer’s work area

is clear of obstruction and

properly organised.

Block laying:

• use eye protection whilst cutting

the banding on packs.

• ensure blocks do not fall when

packaging is removed.

• load blocks out to above

knee height.

• handle blocks close to the body.

• raise scaffolding to keep

blockwork below shoulder height.

• raise mortar boards to a

convenient working height to

avoid bending.

• use eye protection and dust

suppression or extraction

measures when cutting or

chasing blocks.

Further information on health and

safety issues may be found in our

Health and Safety data sheet.

47


TopblockTarmac Topblock, the UK’s leading block manufacturer, offers a comprehensive range whichincludes aircrete, dense and lightweight concrete blocks. The breadth of range coupled withlong experience of the construction industry, enables Topblock to supply blocks which meetthe demands made of today’s building materials.

Backed by the resources of Tarmac Heavy Building Materials (UK), Topblock has developed anetwork of modern factories and depots which give a good geographical coverage, and aresupported by Topblock’s national sales and technical advisory service.

The Company has a policy of continuous improvement and product development.Therefore information contained in this literature is subject to alteration without notice.

Technical servicesA comprehensive technical advisory service is available to specifiers and users of our products.

Thermal U-value calculation and condensation risk analysis;

Movement Appraisal of movement joint and bed joint reinforcement requirements;

Structural Calculations to support the use of blockwork under vertical loading;Recommended sizes for non-loadbearing walls;

General Recommendations for block types (eg below DPC and party walls);Finishes to blockwork;Sitework.

Topblock’s technical staff are available to answer telephone or writtenenquiries:

Tarmac Topblock LimitedTechnical Services Department,Ford Airfield Industrial Estate,Ford, Arundel, BN18 0HYTelephone: 01903 723 333Fax: 01903 730 884

Topblock’s Specifier Services provides project designers with advice on the selection and use of Topblock’s products from the initial design concept through to project completion.

Tarmac Topblock LimitedSpecifier Services, The Building Centre,26 Store Street, London WC1E 7BTTelephone: 0171 631 0730Fax: 0171 631 1635

Tarmac Topblock LimitedWergs Hall, Wergs Hall Road, Wolverhampton, WV8 2HZ

Documents

Top Block Design