NHBC standards and tolerances for dry lining and plastering

The NHBC Standards are the technical requirements, performance standards and guidance NHBC sets for the design and construction of the new homes it registers. The Technical Requirements must be met by the builder. A dry liner or plasterer working for that builder is building to them too.

NHBC describes the Standards as guidance on the requirements to achieve its warranty and insurance. Chapter 2.1 adds that they are not a complete specification for use in contracts.

NHBC now gives the Standards to registered customers and their subcontractors through a log in. The 2024 edition is still open online, and this guide quotes its figures.

NHBC Standards 2026 apply to every NHBC registered home whose foundations are begun on or after 1 January 2026, throughout the UK unless otherwise stated. The edition follows the date the foundations started. A plot whose foundations went in during 2025 stays on the 2025 edition, even if it is boarded this year.

NHBC reports that 1.2% of clauses in the 2026 edition carry changes that represent new positions. Its list of the most significant changes names no change to chapters 9.1 or 9.2. One change does touch the trade. Chapter 10.1 now requires plasterboard ceilings, as absorbent materials, to be separated from single-skin masonry walls.

Check the 2024 figures below against the edition for your plot before relying on them in a dispute.

Part 9, Finishes, holds the two chapters that matter. Chapter 9.1, A consistent approach to finishes, sets the tolerances a finished surface is judged against. Chapter 9.2, Wall and ceiling finishes, covers how plastering and dry lining are done. Chapter 2.1 holds the Technical Requirements behind both.

Clause 9.1.1 says the tolerances apply when the home is substantially complete and ready for NHBC pre-handover inspection. NHBC also uses them during construction and under section 2 of Buildmark. Acceptability of a finish is in the opinion of NHBC, and any remedy should be proportionate.

• 2.1 The Standards and Technical Requirements: R1 statutory, R3 materials, R4 workmanship
• 9.1.1 Compliance: when and how the finish tolerances are applied
• 9.1.3 Internal walls and ceilings: flatness, plumb, level, corners and viewing
• 9.1.4 Doors and windows: reveals, heads and sills of internal openings
• 9.2.3 Plastering: backgrounds, mixes, coats and thickness
• 9.2.4 Dry lining: when to start, support, fixing and jointing

Under clause 9.1.3, a plastered or dry lined wall should be flat within plus or minus 3mm under a 2m straightedge with equal offsets, and no more than 8mm out of plumb up to 3m high. Board joints should not be readily visible, and should sit within plus or minus 3mm under a 450mm straightedge.

How the surface is viewed matters as much as the figures. NHBC says plastered and dry lined surfaces are viewed from 2m in natural daylight, with no artificial light shining on the surface, and with wall lights and uplighters switched off.

Clause 9.1.3 also asks for jointing tape fully covered and no visible gaps around switch plates. It accepts some tooling marks in plaster and shrinkage cracks up to 2mm wide at junctions.

Clause 9.2.4 says dry lining should not start until the building is substantially weatherproofed and structural timber is at a moisture content of 20% or less. Finishes should follow as soon as possible after boarding.

For plastering, clause 9.2.3 asks for services hidden by plaster to be completed and tested first. A mix should never combine Portland cement and gypsum plaster.

• Damaged boards are not used, and boards go up face side out
• Cut edges finish over a support or nogging, except where necessary at perimeters
• Screws do not project above the board, and sit at least 10mm from paper-bound edges, 13mm from cut ends and 6mm from the edge of timber members
• Ceiling boards are staggered to reduce the risk of cracking
• Joints are taped and filled, including the abutments to ceilings and internal walls
• On walls or ceilings with fire resistance, fixings follow the board or system manufacturer's fire test evidence

The Building Regulations are the legal requirement. The NHBC Standards are the warranty provider's requirements on top. Technical Requirement R1 says work shall comply with all relevant Building Regulations, and NHBC will generally accept work that does, except where it sets a higher standard.

The manufacturer's instructions carry weight inside the Standards. For ceilings, the 2024 edition lets joist spacing and noggings follow the board or system manufacturer's instructions or fire test evidence. Where a lining contributes to fire resistance, clause 9.2.4 points back to the Building Regulations for its performance.

Clause 9.1.1 says its tolerances take precedence over other recommendations for finishes on an NHBC home. Other warranty providers, such as LABC Warranty and Premier Guarantee, publish their own technical manuals.

These checks are common trade practice, not NHBC requirements. They catch the faults that later show up against chapter 9.1 at the pre-handover inspection, when putting them right means cutting out finished work.

Before the NHBC inspection, walk each room in daylight with the lights off and look from 2m. Run a 2m straightedge over walls and ceilings, a 450mm straightedge across joints, and a level down each reveal. Check the tape is covered and that switch plates sit tight to the wall.

• Plot weathertight, with windows in and external doors or temporary boards fitted
• A moisture meter reading taken on studs and joists before boarding
• Noggings in for board edges, and pattresses for wall cupboards, radiators and grab rails
• First fix services tested, and back boxes set to the finished board line
• Air and vapour control layers taped and sealed where the design has them
• Board type on the stack matched to the specification, room by room, for fire and moisture resistant boards