Technical Guidance

Expanding on and explaining the NHBC Standards

To help you interpret and apply the NHBC Standards we produce the following Technical Guidance Documents. They each expand on and explain a specific part of the NHBC Standards.

They are designed for use by competent construction industry workers and are for general guidance only. They do not constitute professional advice.

All information relates to circumstances prevailing at the date of publication and will not be updated to reflect subsequent developments.


New home built alongside existing home 
Japanese Knotweed 
Conversions and renovations
The Use of Magnesium Oxide ("MgO") Building Boards on NHBC Warranty sites

NHBC Standards Chapter 2.1 The Standards and Technical Requirements

Independent technical approvals authorities (NEW June 2020)

NHBC Standards Chapter 4.2 Building near trees

Strip/trench fill foundations - slip membranes

NHBC Standards Chapter 4.3 (formerly Ch 4.4) Strip and trench fill foundations

Foundation concrete 
Steps in foundations 
Strip and trench fill foundations on level sites

NHBC Standards Chapter 4.4 (formerly Ch 4.5) Raft, pile, pier and beam foundations

Raft foundations - edge detail

NHBC Standards Chapter 5.2 Suspended ground floors

In-situ concrete suspended ground floors 
Precast concrete floor planks to ground floors 
Radon protection - provision of sump 
Ventilators in compartment walls beneath suspended ground floors

NHBC Standards Chapter 5.3 Drainage below ground

Drainage - connections to pre-formed inspection chamber bases
Lightweight drainage covers 
Access to manholes/inspection chambers 
'Y' junctions in drains under buildings 
Field drainage systems in septic tanks and small private sewerage treatment plants 
Underground drainage - pipe cross-overs

NHBC Standards Chapter 5.4 Waterproofing of basements and other below ground structures

Waterproofing of basements and other below ground structures
Waterproofing admixtures (NEW March 2020)

NHBC Standards Chapter 6.1 External masonry walls

Partial fill insulation to gable walls 
Small pediment gable walls 
Cavity trays to openings with soldier courses or stone lintels 
Dpc trays to rendered walls (Revised March 2017) 
Installation of lead flashings 
Bedding lintels 
Movement joints below dpc 
Restraint straps to gable walls of garages 
Damp proofing around meter boxes 
Movement joints in clay brick masonry 
Cavity trays to bay windows 
Masonry bed joint reinforcement 
Toothing of brickwork 
Concrete fill in a cavity wall 
Ducts/flues through core drilled holes 
Block bonding 
Movement joints in masonry - timber framed external walls  
Lintels within coastal sites 
Lintels  to walls over drive-through access to houses (England and Wales) 
Lintels over wide garage openings 
Wall ties at movement joints 
Face fixed restraint straps to gable walls in buildings 
Air bricks to underfloor voids - relationship to ground levels 
Movement joints in masonry walls 
Forming stop ends to cavity trays 
Thin joint mortars
Wall ties at jambs with full fill cavity board insulation
Stone coursing and wall ties (NEW October 2018)
Fixing tiling battens to masonry (NEW October 2018)

NHBC Standards Chapter 6.2 External timber framed walls

Socket outlets - fire barriers 
Ventilation of cavities 
External timber framed walls - movement gaps at eaves and verges 
Rendering on timber framed walls

NHBC Standards Chapter 6.3 Internal walls

Firestopping to garage walls 
Separating walls - cavity insulation (withdrawn pending review March 2016) 
Dpcs under timber soleplates to internal partitions 
Separating wall construction within roof spaces 
Timber stud partitions 
Sockets and switches in light steel framed separating walls

NHBC Standards Chapter 6.4 Timber and concrete upper floors

End support to chipboard flooring 
Noggings for lateral restraint straps 
Bolt fixing of multiple joists 
Strutting to floor joists 
Sealing around ends of engineering joists 
Support of plasterboard 
Support of joist hangers 
Recessed light fittings in ceilings to intermediate floors in houses (revised August 2019)
Lateral restraint straps to beam and block and precast or prestressed intermediate floors

NHBC Standards Chapter 6.5 Steelwork

Steel beams - parallel connections 
Perforated padstones

NHBC Standards Chapter 6.6 Staircases

Handrail to staircases - tapered treads/winders (Revised October 2018)
Stair nosings 
Guarding to treads and risers 
Risers to private stairs - thick floor coverings 
Nosings to stairs in common areas

NHBC Standards Chapter 6.7 Doors, windows and glazing

Gaps around windows (Revised March 2017) 
Background ventilation to utility rooms 
Gaps around timber windows and timber door frames 
Door between an integral garage and the dwelling - security 
Egress windows and conservatories 
Fire doors to bathrooms 
Window restrictors and protection against falling 
View outside main entrance door 
Door Ironmongery - Students accommodation 
Door limitation devices 
Marking of insulating glass units 
Marking of safety glass
Accessible windows (NEW May 2019)

NHBC Standards Chapter 6.8 Fireplaces, chimneys and flues

Installation of gas flue pipes in roof spaces 
Guarding to gas flue terminals 
Termination of horizontal flues

NHBC Standards Chapter 6.9 Curtain walling and cladding

Curtain walling formed from stacked windows and spandrel panels

NHBC Standards Chapter 7.1 Flat roofs and balconies

Balcony drainage 
Timber balconies and terraces (Revised October 2018)

NHBC Standards Chapter 7.2 Pitched roofs

Diagonal bracing to double hipped roof 
Plasterboard fire-resisting ceiling in contact with single leaf masonry 
Use of nail guns for fixing trussed rafter bracing 
Wall plates - bedding, lengths and joints 
Bedding verge tiles 
Lateral restraint provided by gable ladders (Revised March 2017) 
Bracing of mono-pitch roof trusses 
Pitched roofs - bedding verge undercloaks 
Attic trusses - bracing 
Pitched roofs to garages - holding down straps 
Roofng underlay at eaves level 
Ventilation of small roofs 
Fixing valley trussed rafters (diminishing trussed rafters) 
Canopy flashings 
Diagonal bracing to trussed rafters 
Fixing roof tiles in valleys 
Loft hatches and fire resistance 
Vapour permeable underlays (VPUs) and roof void ventilation (withdrawn December 2016. Now covered by VPU high level ventilation in Standards) 
Fixing tiling battens using nail guns 
Slate hook fixing 
Tiling battens 
Access to roof voids
Spandrel panels to cold roofs (January 2018)
Eaves ventilation trays and VPU’s (NEW October 2018)
Lateral restraint at rafter and ceiling levels (NEW March 2020)
Reclaimed roof tiles and slates (NEW March 2020)

NHBC Standards Chapter 8.1 Internal services

Discharge pipes from UVHWSS in garages 
Earth bonding - certificate of compliance 
Pipe insulation in airing cupboards 
Earth bonding plastic plumbing 
Use of flexible ducting to connect SVP 
Insulation of heating pipes in timber floors 
Electrical - earth bonding metal back boxes 
Sound insulation of soil pipes in floor voids 
Extract fans - air leakage 
Plastic plumbing - pipe support 
Plastic plumbing - insulation 
Air Admittance Valves 
Wiring to wall lights 
Consumer unit - labelling 
Metal splashbacks - earthing/bonding 
Sound proofing to SVP's 
Support to cables in cable trays 
Electrical fittings near cookers, sinks and wash basins 
Consumer units - blanking pieces 
Tracer tapes to plastic water pipes 
Rodding access to soil and vent pipes (Revised March 2017) 
Discharge pipes from unvented hot water storage systems 
Protection of electric cables in walls or flat and sloping ceilings 
Disconnection of built-in kitchen appliances 
Flush mounted electrical accessories in partitions (NEW March 2017)
Mounting height consumer units (NEW October 2018)
Soundproofing to soil and vent pipes (NEW June 2020)
Protective Equipotential Bonding (PEB) of Gas Installation pipework (NEW June 2020)
Pipe insulation with combi boilers (NEW June 2020)

NHBC Standards Chapter 9.2 (formerly Ch 8.2) Wall and ceiling finishes

Edges of ceramic tiling 
Dry lining to walls with chemical dpcs 
Dry lining walls with different types of masonry 
Edge sealing to dry lining
Perimeter support to plasterboard ceilings clarification (NEW March 2020)

NHBC Standards Chapter 9.3 (formerly Ch 8.3) Floor finishes

Fibre reinforced screeds

NHBC Standards Chapter 10.1 (formerly Ch 9.1) Garages

Garage - concrete floors 
Garage wall construction 
Compartment walls between garages (Revised March 2017) 
Carports - fire separation

NHBC Standards Chapter 10.2 (formerly Ch 9.2) Drives, paths and landscaping

Log retaining walls (withdrawn January 2016. Now included in NHBC Standards)
Profles for access steps 
Disabled access to principal entrances (England and Wales) 
Pedestrian access 
Guarding to retaining structures
External steps - mobility access (England and Wales) 
Retaining walls across private gardens 
Guarding to retaining structures in communal areas 
Handrails to steps in paths (withdrawn January 2016. Now in NHBC Standards)
Paths used for the removal of refuse (Revised March 2017)
Proprietary retaining wall systems (NEW March 2020)