When you purchase a new build property, you expect the internal finishes to be completed to a high standard. The NHBC Standards 2026, Chapter 9.2, sets out the technical requirements that builders must follow when completing wall and ceiling finishes. Understanding these standards can help you identify potential defects and know what to look for when inspecting your new home.
9.2.1 Compliance
All wall and ceiling finishes in your new build home must comply with the NHBC Technical Requirements. This means that builders must follow specific guidance to ensure finishes are completed to an acceptable standard. When we conduct a snagging inspection, we assess visible finishes against these requirements to identify any defects that may need rectifying before or after completion.
9.2.2 Provision of Information
Builders are required to produce clear designs and specifications that include all relevant information about the finishes in your home. This documentation should cover details such as the schedule of finishes throughout the property, plaster thickness and mix requirements, fixing specifications for dry lining, and the extent of tiled surfaces. While you may not see these specifications directly, they form the basis of what your builder has committed to delivering.
9.2.3 Plastering
Plastering must provide an adequate substrate for decorative finishes such as paint or wallpaper. The design, preparation, and application of plasters should conform to British Standards including BS EN 13914-2 and BS 8481. Where plaster contributes to fire resistance or sound insulation, it must meet the relevant Building Regulations requirements.
The background surface must be properly prepared before plastering, with appropriate treatment to ensure adequate bonding. Mixed background materials, such as where concrete meets brickwork, can lead to cracking due to differential movement, and builders should take precautions such as using metal lathing at these junctions.
Plaster thickness varies depending on the surface being plastered. For walls, the maximum thickness on brickwork and blockwork is 13mm, applied in at least two coats. Plasterboard walls require only one coat, sufficient to provide a crack-free surface. For ceilings, concrete requires two coats with a maximum thickness of 10mm, whilst plasterboard ceilings need only a skim coat. Finished surfaces should be reasonably flat and even, with external angles and reveals properly formed.
9.2.4 Dry Lining
Dry lining, commonly known as plasterboard, must provide an adequate substrate for decorative finishes. There are four key aspects that builders must address: installation, air and vapour control, detailing and support, and fixing.
9.2.4.1 Installation
Dry lining work should not commence until the building is substantially weatherproofed and structural timber components have reached a moisture content of 20% or less. This is important because excessive moisture can cause boards to warp or joints to crack over time. Where dry lining contributes to fire resistance, it must perform in accordance with the relevant Building Regulations, and gap sealing should be specified where necessary to prevent draughts.
9.2.4.2 Air and Vapour Control (AVCL)
Air and vapour control layers are used to reduce the risk of interstitial condensation and enhance airtightness. These must be installed in accordance with the relevant NHBC chapters depending on the construction type, whether timber framed walls, light steel framed walls, flat roofs, or pitched roofs. Proper installation of these layers is crucial for the long-term performance of your home’s thermal envelope.
9.2.4.3 Detailing and Support
The support requirements for wall and ceiling linings depend on board type, thickness, and any performance requirements such as fire resistance. Typically, studs and joists should be at no greater than 600mm centres, with intermediate and perimeter noggings provided where specified. Cut edges of boards should finish over a support or nogging, and ceiling boards should be staggered to minimise the risk of cracking.
Joints between boards should be neatly formed, flush, and suitably finished with scrim tape or paper tape where boards are to be plastered, or with tape and filler where they are not. Where double layers of board are used, joints should typically be staggered between layers to improve performance.
9.2.4.4 Fixing
Boards should be fixed to timber or metal using dry wall screws, or to masonry using adhesive dabs. Screws must not project above the board surface and should be positioned at least 10mm from paper-bound edges and 13mm from cut ends. Typical screw fixing centres are 230mm for ceilings and 300mm for walls.
Where dry lining is fixed with adhesive dabs, these should be at 300mm centres measured vertically, with each dab being 50mm to 75mm wide and approximately 250mm long. A continuous ribbon of adhesive should be applied to the perimeter of external walls and around openings to prevent air infiltration.
9.2.5 Ceramic Wall Tiling
Ceramic wall tiling must provide a surface adequate for its location and intended use, considering both appearance and durability. Tiling and backing surfaces should conform to BS 5385. Where a fixed shower or showerhead is provided over a bath at a height permitting someone to stand under it, a screen or other means of containing water should be provided, and surfaces that will become regularly wetted should be tiled or have an appropriate water-resistant finish.
Backing surfaces for tiling have specific requirements. They must be strong enough to support the weight of the adhesive and tiles, provide an adequate mechanical key, be sufficiently flat to achieve an even tiled surface, and be dry, clean, and free from any substances likely to affect the bond. The backing should be reasonably even, within plus or minus 3mm when checked with a 2m straight edge. Where dry lining is fixed with adhesive dabs, it should be completed at least 10 days before wall tiling takes place to ensure adequate curing.
The appropriate backing surface depends on the conditions. For normal internal walls that do not form part of a bath or shower enclosure, cement rendering, masonry, gypsum plaster, or plasterboard are all acceptable without additional waterproofing. For shower and bath enclosures, or wet rooms, specific guidance in Technical Guidance Note 9.2/06 should be followed regarding backing surfaces and tanking systems.
When tiling is installed, courses should be straight and even to form a plane and regular surface, especially around fittings and fixtures. There should be no cut or unfinished tiles at exposed edges or external corners. Movement joints should be built into tiling at 3m to 4.5m centres both vertically and horizontally, and at vertical internal corners in large tiled areas. Grouting should be as specified in the design and applied using cement-based epoxy resin or a proprietary product.
9.2.6 Further Information
The NHBC Standards reference several British Standards and industry guidance documents that provide additional detail on wall and ceiling finishes. These include BS 8000-8 for dry lining systems, BS 8000-11 for wall and floor tiling, and various publications from The Tile Association covering internal tiling, wet rooms, and showers.
How a Snagging Inspection Can Help
A professional snagging inspection can identify visible defects in your wall and ceiling finishes, such as uneven plastering, poorly finished joints in dry lining, cracks at junctions between different background materials, and issues with tiling including uneven courses, poor grouting, or inadequate sealing around sanitary fittings. While a snagging inspection is not a full structural survey and cannot assess concealed elements such as the installation of air and vapour control layers or the adequacy of fixings behind finished surfaces, it provides valuable identification of cosmetic and visible finishing defects that your builder should rectify.
If you are purchasing a new build home and want peace of mind that the wall and ceiling finishes meet the required standards, our team of experienced inspectors can help identify any snags that need addressing before or after completion.
