- Home
- 1 Welcome
- 2 Introduction
- 3 General
- 3.1 Concrete and its reinforcement
- 3.1.1 Compliance
- 3.1.2 Provision of information
- 3.1.3 Storage of materials
- 3.1.4 Site-mixed concrete
- 3.1.5 Ready-mixed concrete
- 3.1.6 Concrete specification
- 3.1.7 Admixtures
- 3.1.8 Special types of concrete
- 3.1.9 Design of reinforced concrete
- 3.1.10 Installation of reinforcement
- 3.1.11 Blinding concrete
- 3.1.12 Formwork
- 3.1.13 Before concreting
- 3.1.14 Casting
- 3.1.15 Curing
- 3.1.16 Testing
- 3.1.17 Glossary
- 3.2 Cold weather working
- 3.3 Timber preservation (natural solid timber)
- 3.1 Concrete and its reinforcement
- 4 Foundations
- 4.1 Land quality – managing ground conditions
- 4.1.1 Compliance
- 4.1.2 Initial Assessment – desk study (all sites)
- 4.1.3 Initial Assessment – walkover survey (all sites)
- 4.1.4 Initial Assessment – results
- 4.1.5 Basic Investigation (sites where hazards are not identified or suspected)
- 4.1.6 Detailed Investigation (sites where hazards are identified or suspected)
- 4.1.7 Managing the risks (sites where hazards are found)
- 4.1.8 Unforeseen hazards
- 4.1.9 Documentation and verification
- 4.1.10 Guidance for investigations
- 4.1.11 Further information
- 4.2 Building near trees
- 4.2.1 Compliance
- 4.2.2 Provision of information
- 4.2.3 Building near trees
- 4.2.4 The effects of trees on shrinkable soils
- 4.2.5 Foundations in all soil types
- 4.2.6 Excavation of foundations
- 4.2.7 Foundations in shrinkable soils
- 4.2.8 Design and construction of foundations in shrinkable soils
- 4.2.9 Foundation depths for specific conditions in shrinkable soils
- 4.2.10 Heave precautions
- 4.2.11 New drainage
- 4.2.12 Foundation depth charts
- 4.2.13 Foundation depth tables
- 4.2.14 Example
- 4.2.15 Further information
- 4.3 Strip and trench fill foundations
- 4.3.1 Compliance
- 4.3.2 Provision of information
- 4.3.3 Ground conditions
- 4.3.4 Hazardous ground
- 4.3.5 Setting out
- 4.3.6 Services and drainage
- 4.3.7 Safe transmission of loads
- 4.3.8 Sloping ground and stepped foundations
- 4.3.9 Excavations
- 4.3.10 Reinforcement
- 4.3.11 Concrete
- 4.3.12 Movement joints
- 4.3.13 Construction joints
- 4.4 Raft, pile, pier and beam foundations
- 4.4.1 Compliance
- 4.4.2 Provision of information
- 4.4.3 Site conditions
- 4.4.4 Hazardous ground
- 4.4.5 Services and drainage
- 4.4.6 Safe transmission of loads
- 4.4.7 Construction
- 4.4.8 Engineer checks
- 4.4.9 Compressible materials
- 4.4.10 Reinforcement
- 4.4.11 Concrete
- 4.4.12 Movement joints
- 4.4.13 Resistance to moisture
- 4.5 Vibratory ground improvement techniques
- 4.5.1 Compliance
- 4.5.2 Hazardous sites and ground hazards
- 4.5.3 Desk study and site investigation
- 4.5.4 Confirmation of suitability for treatment
- 4.5.5 Suitability of ground conditions
- 4.5.6 Compatibility of the ground, design and treatment
- 4.5.7 Acceptable methods
- 4.5.8 Materials for use as fill
- 4.5.9 Granular material
- 4.5.10 Sitework
- 4.5.11 Adjacent excavations
- 4.5.12 Verification of completed treatment
- 4.1 Land quality – managing ground conditions
- 5 Substructure, Ground Floors, Drainage and Basements
- 5.1 Substructure and ground-bearing floors
- 5.1.1 Compliance
- 5.1.2 Provision of information
- 5.1.3 Transfer of loads
- 5.1.4 Ground conditions
- 5.1.5 Services and drainage
- 5.1.6 Ground below fill
- 5.1.7 Fill below floors
- 5.1.8 Infill up to 600mm deep
- 5.1.9 Materials used for fill
- 5.1.10 Harmful or toxic materials
- 5.1.11 Regulatory solutions
- 5.1.12 Walls below the DPC
- 5.1.13 Durability
- 5.1.14 Mortar
- 5.1.15 Wall ties
- 5.1.16 Blinding
- 5.1.17 Ground floor slab and concrete
- 5.1.18 Laying the ground-bearing floor slab
- 5.1.19 Damp proof course
- 5.1.20 Damp proofing concrete floors
- 5.1.21 Thermal insulation
- 5.1.22 Installation of insulation
- 5.1.23 Further information
- 5.2 Suspended ground floors
- 5.2.1 Compliance
- 5.2.2 Provision of information
- 5.2.3 Contaminants
- 5.2.4 Proprietary systems
- 5.2.5 Transfer of loads: concrete floors
- 5.2.6 Reinforced concrete
- 5.2.7 Construction of suspended concrete ground floors
- 5.2.8 Transfer of loads: timber floors
- 5.2.9 Thermal insulation and cold bridging
- 5.2.10 Damp-proofing and ventilation
- 5.2.11 Floor finishes
- 5.2.12 Floor decking
- 5.3 Drainage below ground
- 5.3.1 Compliance
- 5.3.2 Provision of information
- 5.3.3 Preliminary work
- 5.3.4 Foul and surface water disposal
- 5.3.5 Drainage system performance
- 5.3.6 Ground water drainage
- 5.3.7 Design to avoid damage and blockages
- 5.3.8 Durability
- 5.3.9 Septic tanks and cesspools
- 5.3.10 Septic tanks
- 5.3.11 Surface water soakaways
- 5.3.12 Component requirements
- 5.3.13 Excavation
- 5.3.14 Protection of pipework
- 5.3.15 Laying pipework
- 5.3.16 Protection of work
- 5.3.17 Testing
- 5.4 Waterproofing of basements and other below ground structures
- 5.1 Substructure and ground-bearing floors
- 6 Superstructure (excluding roofs)
- 6.1 External masonry walls
- 6.1.1 Compliance
- 6.1.2 Provision of information
- 6.1.3 Structural design
- 6.1.4 Fire resistance
- 6.1.5 Acoustic resistance
- 6.1.6 Exposure
- 6.1.7 Thermal insulation
- 6.1.8 Concrete blocks
- 6.1.9 Bricks
- 6.1.10 Stone masonry
- 6.1.11 Construction of masonry walls
- 6.1.12 Lintels
- 6.1.13 Materials suitable for mortar
- 6.1.14 Mortar
- 6.1.15 Render
- 6.1.16 Cladding
- 6.1.17 DPCs and cavity trays
- 6.1.18 Wall ties
- 6.1.19 Handling materials
- 6.1.20 Cold weather working
- 6.2 External timber framed walls
- 6.2.1 Compliance
- 6.2.2 Provision of information
- 6.2.3 Design checking and certification
- 6.2.4 Load-bearing walls
- 6.2.5 Fixing the frame
- 6.2.6 Nails and staples
- 6.2.7 Sheathing
- 6.2.8 Differential movement
- 6.2.9 Fire resistance
- 6.2.10 Protection from moisture
- 6.2.11 Timber preservation
- 6.2.12 Vapour control layers
- 6.2.13 Breather membranes
- 6.2.14 Wall ties and fixings
- 6.2.15 Insulation
- 6.3 Internal walls
- 6.3.1 Compliance
- 6.3.2 Provision of information
- 6.3.3 Supporting load-bearing internal walls
- 6.3.4 Masonry walls
- 6.3.5 Load-bearing timber walls
- 6.3.6 Fire resistance
- 6.3.7 Sound insulation
- 6.3.8 Partitions: internal non load-bearing
- 6.3.9 Construction of timber partitions
- 6.3.10 Construction of steel framed partitions
- 6.3.11 Construction of proprietary systems
- 6.3.12 Plasterboard
- 6.3.13 Damp-proof courses
- 6.3.14 Components
- 6.4 Timber and concrete upper floors
- 6.4.1 Compliance
- 6.4.2 Provision of information
- 6.4.3 Upper floor design
- 6.4.4 Fire spread
- 6.4.5 Sound insulation
- 6.4.6 In-situ concrete floors and concreting
- 6.4.7 Precast concrete
- 6.4.8 Timber joist spans
- 6.4.9 Timber joists
- 6.4.10 Construction of timber floors
- 6.4.11 Joists supported by intermediate walls
- 6.4.12 Joists connected to steel
- 6.4.13 Joists into hangers
- 6.4.14 Timber joist and restraint strap
- 6.4.15 Strutting
- 6.4.16 Joists and openings
- 6.4.17 Multiple joists
- 6.4.18 Notching and drilling
- 6.4.19 Floor decking
- 6.4.20 Floating floors or floors between homes
- 6.5 Steelwork
- 6.6 Staircases
- 6.6.1 Compliance
- 6.6.2 Provision of information
- 6.6.3 Fire precautions
- 6.6.4 Lighting
- 6.6.5 Safe transmission of loads
- 6.6.6 Headroom and width
- 6.6.7 Design of steps
- 6.6.8 Landings
- 6.6.9 Guarding
- 6.6.10 Handrails
- 6.6.11 Timber staircases
- 6.6.12 Timber and wood-based products
- 6.6.13 Finished joinery
- 6.6.14 Concrete staircases
- 6.6.15 Steel staircases
- 6.6.16 Staircase units
- 6.6.17 Fixings
- 6.6.18 Protection
- 6.7 Doors, windows and glazing
- 6.8 Fireplaces, chimneys and flues
- 6.8.1 Compliance
- 6.8.2 Provision of information
- 6.8.3 Solid fuel – fireplaces and hearths
- 6.8.4 Solid fuel – combustion air
- 6.8.5 Solid fuel – flue pipes
- 6.8.6 Solid fuel – chimneys
- 6.8.7 Solid fuel – outlets and terminals
- 6.8.8 Gas – fireplaces and hearths
- 6.8.9 Gas – combustion air
- 6.8.10 Gas – flue pipes
- 6.8.11 Gas – chimneys
- 6.8.12 Gas – outlets and terminals
- 6.8.13 Oil – fireplaces and hearths
- 6.8.14 Oil – combustion air
- 6.8.15 Oil – flue pipes
- 6.8.16 Oil – chimneys
- 6.8.17 Oil – outlets and terminals
- 6.8.18 All – fireplaces and hearths
- 6.8.19 All – fireplace surrounds
- 6.8.20 All – flue pipes
- 6.8.21 All – flue liners
- 6.8.22 All – flues
- 6.8.23 All – chimneys
- 6.8.24 Masonry
- 6.8.25 Mortar
- 6.8.26 DPC
- 6.8.27 Flashings
- 6.8.28 Terminals
- 6.8.29 Flue testing
- 6.8.30 Further information
- 6.9 Curtain walling and cladding
- 6.9.1 Compliance
- 6.9.2 Provision of information
- 6.9.3 Certification
- 6.9.4 Loads
- 6.9.5 Support and fixings
- 6.9.6 Durability
- 6.9.7 Interfaces
- 6.9.8 Insulation
- 6.9.9 Damp proofing and vapour control
- 6.9.10 Installation and tolerances
- 6.9.11 Electrical continuity and earth bonding
- 6.9.12 Maintenance
- 6.9.13 Glazing, gaskets and sealants
- 6.9.14 Cavity barriers and firestops
- 6.9.15 Ventilation screens
- 6.9.16 Handling and storage
- 6.9.17 Curtain walling
- 6.9.18 Rainscreen cladding
- 6.9.19 Insulated render and brick slip cladding
- 6.10 Light steel framing
- 6.10.1 Compliance
- 6.10.2 Provision of information
- 6.10.3 Structural certification
- 6.10.4 Structural design of load-bearing floors and walls
- 6.10.5 Structural design of infill walls
- 6.10.6 Roofs
- 6.10.7 Steel and fixings
- 6.10.8 Detailing of steel joists
- 6.10.9 Restraint
- 6.10.10 Construction of load-bearing walls and external infill walls
- 6.10.11 Interfaces with staircases
- 6.10.12 Fixing floor decking and ceilings
- 6.10.13 Other design issues
- 6.10.14 Behaviour in relation to fire
- 6.10.15 Acoustic performance
- 6.10.16 Moisture control
- 6.10.17 Insulation
- 6.10.18 Vapour control layers
- 6.10.19 Breather membranes
- 6.10.20 Cladding, lining and sheathing boards
- 6.10.21 Wall ties
- 6.10.22 Services
- 6.10.23 Further information
- 6.11 Render
- 6.1 External masonry walls
- 7 Roofs
- 7.1 Flat roofs and balconies
- 7.1.1 Compliance
- 7.1.2 Provision of information
- 7.1.3 Flat roof and balcony design
- 7.1.4 Timber and timber decks
- 7.1.5 Profiled metal decks
- 7.1.6 Concrete decks
- 7.1.7 Thermal insulation and vapour control
- 7.1.8 Waterproofing and surface treatments
- 7.1.9 Green and proprietary roofs
- 7.1.10 Detailing of flat roofs
- 7.1.11 Accessible thresholds
- 7.1.12 Drainage
- 7.1.13 Guarding to balconies
- 7.2 Pitched roofs
- 7.2.1 Compliance
- 7.2.2 Provision of information
- 7.2.3 Design of pitched roofs
- 7.2.4 Protection of trusses
- 7.2.5 Durability
- 7.2.6 Wall plates
- 7.2.7 Joints and connections
- 7.2.8 Restraint
- 7.2.9 Bracing for trussed rafter roofs
- 7.2.10 Strutting for attic trusses and cut roofs that form a floor
- 7.2.11 Support for equipment
- 7.2.12 Access
- 7.2.13 Dormer construction
- 7.2.14 Underlay and sarking
- 7.2.15 Ventilation, vapour control and insulation
- 7.2.16 Firestopping and cavity barriers
- 7.2.17 Battens
- 7.2.18 Roof coverings
- 7.2.19 Fixing tiles and slates
- 7.2.20 Weathering details
- 7.2.21 Valleys and hidden gutters
- 7.2.22 Drainage
- 7.2.23 Fascias and trim
- 7.2.24 Spandrel panels
- 7.1 Flat roofs and balconies
- 8 Services
- 8.1 Internal services
- 8.1.1 Compliance
- 8.1.2 Provision of information
- 8.1.3 Water services and supply
- 8.1.4 Cold water storage
- 8.1.5 Hot water service
- 8.1.6 Soil and waste systems
- 8.1.7 Electrical services and installations
- 8.1.8 Gas service installations
- 8.1.9 Meters
- 8.1.10 Space heating systems
- 8.1.11 Installation
- 8.1.12 Extract ducts
- 8.1.13 Testing and commissioning
- 8.2 Low or zero carbon technologies
- 8.2.1 Compliance
- 8.2.2 Provision of information
- 8.2.3 Clean Air Act
- 8.2.4 System design
- 8.2.5 Access
- 8.2.6 Handling, storage and protection
- 8.2.7 Sequence of work
- 8.2.8 Location
- 8.2.9 Building integration
- 8.2.10 Fixing
- 8.2.11 Electrical installation requirements
- 8.2.12 Pipes, insulation and protection from cold
- 8.2.13 Ground collectors
- 8.2.14 Fuel storage
- 8.2.15 Safe discharge
- 8.2.16 Testing and commissioning
- 8.2.17 Handover requirements
- 8.2.18 Further information
- 8.3 Mechanical ventilation with heat recovery
- 8.1 Internal services
- 9 Finishes
- 10 External works
- 10.1 Garages
- 10.2 Drives, paths and landscaping
- 10.2.1 Compliance
- 10.2.2 Provision of information
- 10.2.3 Stability
- 10.2.4 Freestanding walls and retaining structures
- 10.2.5 Guarding and steps
- 10.2.6 Drives, paths and landscaping
- 10.2.7 Materials
- 10.2.8 Garden areas within 3m of the home
- 10.2.9 Garden areas
- 10.2.10 Timber decking
- 10.2.11 Landscaping
6.1.14Mortar
Mortar shall be of the mix proportions necessary to achieve adequate strength and durability and be suitable for the type of masonry. Issues to be taken into account include:
- sources of sulfate
- admixtures and additives
- preparing mortar
- joints.
Unless recommended otherwise by the brick manufacturer, the mixes in Table 6 should be used for clay bricks. In the case of concrete or calcium silicate bricks, particular attention should be paid to the manufacturer’s recommendations.
Table 6: Mortar mixes using ordinary Portland or sulfate-resisting cements
Location | Recommended cement:lime: sand mix | Recommended cement:sand mix with air entraining plasticiser | Recommended masonry cement: sand mix | Mortar designation to BS EN 1996-1-1 | |
---|---|---|---|---|---|
General wall area above the DPC | In areas of severe or very severe exposure – high durability Other exposure categories – general use | 1:½:4½ 1:1:5½ | 1:3½ 1:5½ | 1:3 1:4½ | (ii) (iii) |
Below DPC level and in chimney stacks | High durability | 1:½:4½ | 1:3½ | 1:3 | (ii) |
Cappings, copings and sills | Low permeability | 1:0 to ¼:3 | - | - | (i) |
Air-entraining plasticiser can be incorporated in the following general use and high durability mortars:
- 1:1:5½, cement:lime:sand, or
- 1:1:4½, cement:lime:sand.
- follow manufacturer’s recommendations and timescales
- do not use it beyond the time for which it is effective
- protect it against freezing prior to use
- temporary bracing of larger walls, e.g. at gable peaks and long walls, may be necessary due to delayed setting times.
- below the DPC level when sulfates are present in the ground
- when clay bricks (F2,S1 and F1,S1 to BS EN 771) are used
- when there is a high saturation risk (examples below).
- below the DPC
- areas of severe or very severe exposure to driving rain
- parapets
- retaining walls
- freestanding walls
- rendered walls
- chimney stacks.
- only be used where authorised
- not contain calcium chloride
- be dosed and used in accordance with the manufacturer’s recommendations.
- ensure the mix is appropriate for the use and location
- plant and banker boards should be kept clean
- mixers should be kept clean to operate efficiently
- the colour should be consistent.
- mortar which has started to set should not be retempered
- they should have a solid mortar bedding and fully filled perpends, to reduce the risk of rain penetration and dampness in the wall.
- bricks are not frost-resistant, e.g. clay F1,S1 or F1,S2 to BS EN 771, unless the brick manufacturer has confirmed their use for that particular location in writing
- the home is built on steep sloping ground, facing open countryside or within 8km of a coast or large estuary
- bricks are perforated closer than 15mm to the face
- there is no reasonable shelter from driving rain, e.g. from buildings or groups of trees within 50m and of similar height to the home
- the cavity is to be fully filled with cavity insulation.
Retarded mortar
Retarded mortar and most premixed mortars can be used over a longer period of time than site-mixed, cement:lime:sand mortars. When using retarded mortar:
Sources of sulfate
Mortar is vulnerable to deterioration by sulfates, especially when masonry is saturated for long periods of time. Clay bricks contain soluble sulfate (S1 designations have no limit on their sulfate content) and so a suitable mortar should be used.
To reduce risk, sulfate-resisting Portland cement to BS EN 197-1 should be used:
High saturation risk situations are:
Admixtures and additives
Admixtures should:
Mortars containing an air-entraining plasticiser are more resistant to freeze and thaw damage when set, but do not prevent freezing before the mortar is cured.
White cement to BS EN 197 and pigments to BS EN 12878 may be used, but pigments should not exceed 10% of the cement weight, or 3% where carbon black is used.
Preparing mortar
When preparing mortar:
When laying bricks and blocks:
Joints
Jointing is preferable to pointing because it leaves the mortar undisturbed. Struck (or weathered) and bucket handle joints are preferable for external walls. Unless the design states otherwise, only bucket handle or weathered joints should be used.