top block design
TRANSCRIPT
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
T o p b l o c k D e s i g n G u i d e
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.
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T o p b l o c k D e s i g n G u i d e
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
To demonstrate compliance using
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
To demonstrate compliance using
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
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T o p b l o c k D e s i g n G u i d e
80 or less
More than 80 up to 90
SAP Energy Rating
80
81
More than 90 up to 100 82
More than 100 up to 110 83
More than 110 up to 120 84
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 area of exposed elements
Total floor area x 0.57+ 0.36
Total area of exposed elements
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
To demonstrate compliance using
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
To demonstrate compliance using
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
To demonstrate compliance using
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.
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T o p b l o c k D e s i g n G u i d e
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”.
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T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
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T o p b l o c k D e s i g n G u i d e
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
140mm Toplite Standard
100mm Toplite ‘7’
140mm 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
U Values (W/m2K) Insulation & Surface Finish
DPNF
50mm Injected cavity
insulationλ = 0.039
65mm 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
75mm Injected cavity
insulationλ = 0.039
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 Toplite Standard
140mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
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
T o p b l o c k D e s i g n G u i d e
U Values (W/m2K) Insulation & Surface Finish
DPNF
50mm Crown
Dritherm battλ = 0.033
65mm Crown
Dritherm battλ = 0.034
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
Dritherm battλ = 0.036
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 Toplite Standard
140mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
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
U Values (W/m2K) Insulation & Surface Finish
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 Toplite Standard
140mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
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
Key to tables • NF – No finish
• DP – Dense plaster
• LP – Lightweight plaster• DL – Drylining on dabs
(9.5mm plasterboard)
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
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T o p b l o c k D e s i g n G u i d e
U Values (W/m2K) Insulation & Surface Finish
DPNF
30mm Rockwoolλ = 0.033
40mm 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
50mm Rockwoolλ = 0.033
DPNF LP DL
0.43 0.42 0.41115mm Toplite GTI
0.41 0.41 0.40125mm Toplite GTI
140mm Toplite GTI
100mm Toplite Standard
140mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
100mm Hemelite
140mm Hemelite
100mm Lignacite
140mm Lignacite
100mm Topcrete
140mm Topcrete
U Values (W/m2K) Insulation & Surface Finish
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 Toplite Standard
140mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
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
Key to tables • NF – No finish
• DP – Dense plaster
• LP – Lightweight plaster• DL – Drylining on dabs
(9.5mm plasterboard)
12
T o p b l o c k D e s i g n G u i d e
U Values (W/m2K) Insulation & Surface Finish
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 Toplite Standard
140mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
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
100mm Toplite Standard
140mm Toplite Standard
150mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
150mm Toplite ‘7’
Key to tables • NF – No finish
• 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
T o p b l o c k D e s i g n G u i d e
U Values (W/m2K) Insulation
& 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
100mm Toplite Standard
140mm Toplite Standard
150mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
150mm Toplite ‘7’
Table 1.9f: Cavity wall partial fill – 16mm render • 100mm Hemelite Standard • 50mm residual
clear cavity • 25mm Wallmate CW • block • finish
Key to tables • NF – No finish
• DP – 13mm Dense plaster• LP – 13mm Lightweight plaster• DL – Drylining on dabs
(9.5mm plasterboard)• DU – Duplex plasterboard
(9.5mm plasterboard)*
Notes *foil faced Duplex plasterboard on 25mm thick x 38mm wide vertical battens at 400mm horizontal centres
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
T o p b l o c k D e s i g n G u i d e
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 Toplite Standard
140mm Toplite Standard
150mm Toplite Standard
100mm Toplite ‘7’
140mm Toplite ‘7’
150mm Toplite ‘7’
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)• DU – Duplex plasterboard
(9.5mm plasterboard)*• TB1 – 22mm Gyproc
Thermal board LD• TB2 – 35mm Gyproc
Thermal board Plus• TB3 – 40mm Gyproc
Thermal board Super
Notes *foil faced Duplex plasterboard on 25mm thick x 38mm wide vertical battens at 400mm horizontal centres
A 10mm airspace is assumed behind plasterboard and plasterboard laminates
Notes – Denotes U values exceeding 0.70W/m2K
15
T o p b l o c k D e s i g n G u i d e
U Values (W/m2K) Insulation
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.
U Values (W/m2K) Surface Finish
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 Toplite Standard
200mm Toplite Standard
215mm Toplite Standard
190mm Toplite ‘7’
200mm Toplite ‘7’
215mm Toplite ‘7’
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
T o p b l o c k D e s i g n G u i d e
U Values (W/m2K) Surface Finish
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.
U Values (W/m2K) Surface Finish
100mm Toplite Standard
150mm Toplite Standard
215mm Toplite Standard
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
Key to tables • NF – No finish
• DP – 13mm Dense plaster• LP – 13mm Lightweight plaster• DL – Drylining on dabs
(9.5mm plasterboard)• DU – Duplex plasterboard
(9.5mm plasterboard)*
Notes *foil faced Duplex plasterboard on 25mm thick x 38mm wide vertical battens at 400mm horizontal centres
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
T o p b l o c k D e s i g n G u i d e
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
18mm Chipboard and 50mm Jablite
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
T o p b l o c k D e s i g n G u i d e
(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
18mm Chipboard and 25mm Jablite
Withoutfoundation
block
Withfoundation
block
18mm Chipboard and 50mm Jablite
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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)
2 × 100mm HemeliteStandard solid. 75mm cavity
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)
2 × 90mm HemeliteStandard solid. 75mm cavity
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
Weighted sound reduction index, Rw (dB)
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
T o p b l o c k D e s i g n G u i d e
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
Weighted sound reduction index, Rw (dB)
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
Compressive strengthof unit (N/mm2)
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
Compressive strengthof unit (N/mm2)
Characteristiccompressive strength,
fk , (N/mm2)
Block thickness (mm)
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
Table 3.6: Minimum block thickness – walls restrained at both ends
Block thickness (mm)
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
Block thickness (mm)
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
Sealant whererequired
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
T o p b l o c k D e s i g n G u i d e
Figure 4.4 Movement joint continued through rigid finishes
Figure 4.5 Lateral restraintof non-loadbearing walls
Joint filler
Stop bead
Sealant whererequired
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
Wall ties at maximum300mm vertical centres
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 where required
Sealant whererequired
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
T o p b l o c k D e s i g n G u i d e
Figure 4.17 Movement joint to blockworksupported by a steel frame
Wall ties at maximum300mm vertical centres
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
Sealant where required
Flexible ties at max.300mmverticalcentres
Fireprotectionto column
Joint filler
Column
Sealant whererequired
Joint filler
Flexible ties at max.300mmverticalcentres
Topblockblocks
Topblockblocks
Topblockblocks
Topblockblocks
41
T o p b l o c k D e s i g n G u i d e
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
Compressiblejoint filler
Compressiblejoint filler
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
Compressiblejoint filler
42
T o p b l o c k D e s i g n G u i d e
Figure 4.21 Movement joint at reinforced concrete column
Sealant whererequired
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
T o p b l o c k D e s i g n G u i d e
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
Toplite Foundation 3.5N/mm2
Toplite Foundation 3.5N/mm2
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
190mm Toplite GTI, Standard or ‘7’
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
215mm Toplite GTI, Standard or ‘7’
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
T o p b l o c k D e s i g n G u i d e
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