If you have bought a new build home and reported a snag, there is a good chance you have been told it is “within tolerance”. That phrase almost always comes from Chapter 9.1 of the NHBC Standards, “A consistent approach to finishes”. This chapter is the benchmark NHBC and housebuilders use to decide whether the visible finish of a new home is acceptable, from brickwork and plaster to doors, tiles, kitchen units and paintwork.

Understanding Chapter 9.1 helps you tell a genuine defect from a normal characteristic of a new building, and it lets you raise defects in language your housebuilder will recognise. This guide explains what the chapter covers, how it says finishes should be judged, the tolerances it sets for each part of the home, and where its limits lie. All figures are taken from the 2026 edition of the NHBC Standards.

Which edition applies to your home?

The NHBC Standards are updated every year. The 2026 edition applies to NHBC-registered homes whose foundations were begun on or after 1 January 2026. The edition that applies to your home depends on when its foundations were started, not when you bought it. The tolerances in Chapter 9.1 have been stable for several editions, so the guidance below will also be very close to what applies to homes started in recent years.

What is Chapter 9.1 for?

Chapter 9.1 sits in Part 9 of the NHBC Standards, “Finishes”, alongside chapters on wall and ceiling finishes (9.2), floor finishes (9.3), finishes and fitments (9.4) and painting and decorating (9.5). Those chapters mainly explain how finishes should be specified and installed. Chapter 9.1 is different: it explains how the finished result should be judged. Other chapters point back to it, for example Chapter 6.7 says construction tolerances for openings, doors and windows should follow Chapter 9.1, and Chapter 9.2 says dry lining should be finished in accordance with it.

The chapter opens by saying that finishes complying with its guidance “will generally be acceptable”. Clause 9.1.1 then sets out how the guidance works. It is intended to apply when the home is substantially complete and ready for NHBC’s pre-handover inspection. NHBC uses it both during construction and when resolving disputes under section 2 of Buildmark, the builder warranty period. It should be read alongside the performance standards elsewhere in the NHBC Standards, and its tolerances take precedence over other recommendations. Importantly, it is “not intended to deal with every situation which may arise, and discretion should be exercised.”

The general approach: how finishes are judged

The chapter accepts that new homes are built from natural and manufactured materials that move, shrink and vary. It notes that some elements are affected by normal thermal or drying movement, before and after completion, and that some materials, including reclaimed materials, are not uniform and are not intended to be. Some colour and texture variation is therefore inevitable.

Final judgement on appearance rests with NHBC, as the chapter states that acceptability of finished appearances “will be in the opinion of NHBC”. It also sets a principle of proportionality: the work needed to remedy minor variations should be proportionate and appropriate to the circumstances, taking into account how readily visible or extensive the affected area is. In practice, a small blemish inside a cupboard may be treated differently from the same blemish on the main wall of your living room.

Viewing distances and lighting conditions

The most distinctive feature of Chapter 9.1 is that it says where to stand and what light to use when judging a finish. Many disagreements between buyers and builders come down to this. A blemish that shows up under a torch held flat against a wall may be judged acceptable when viewed from 2m in daylight.

External walls, render and cladding are judged in daylight from a minimum distance of 10m, and across the whole wall rather than individual bricks or features. Plastered and dry-lined walls and ceilings are viewed from 2m in natural daylight with no artificial light shining on the surface, and wall lights and uplighters should be switched off. The same 2m daylight rule applies to paintwork and skirting joints, and to sealant joints where the location allows. Glazing is checked in daylight from inside the room at a minimum of 2m, or 3m for toughened, laminated or coated glass. Fitted furniture and sanitary ware are judged much more closely, at 0.5m in daylight. In rooms with no daylight, scratches should be viewed under the fixed wall or ceiling lights, not portable lighting.

For homebuyers, this has two practical consequences. First, use the same viewing conditions when deciding whether to report a cosmetic snag, because that is how NHBC will judge it. Second, the close 0.5m distance for kitchen units, worktops, baths and basins works in your favour: scratches and chips on those items are judged far more strictly than marks on a wall.

External walls (Clause 9.1.2)

Clause 9.1.2 covers fair faced masonry, render, curtain walling, rainscreen cladding, brick slip cladding, timber cladding, tile hanging and cast stone. Tolerances and appearance are considered for the entire wall, not for individual bricks, bed joints or design features such as quoins, soldier courses and plinths, and are judged in daylight from at least 10m.

Brickwork and blockwork

Fair faced masonry should be reasonably uniform in texture, finish and colour, including the mortar, and should not have excessive colour banding. It should not have significant cracks in the facing bricks or other damage, such as chips and marks greater than 15mm in diameter. The chapter also explains what you can expect to see: some mortar blemishes on individual bricks, some variation in colour and texture, and efflorescence, the white salty deposit on new brickwork, which it describes as not harmful and generally disappearing over time. Some brick products have features or marks larger than 15mm by design, and minor shrinkage cracking may occur between bricks and mortar joints.

For line and level, fair faced masonry should be straight on plan within ±8mm in any length of wall up to 5m, and straight in section within ±8mm per storey height up to 3m. It should be no more than 8mm out of plumb in any storey up to 3m, with taller walls limited to 8mm per storey and 12mm in total. External reveals should deviate by no more than 4mm over 1m.

Bed joints should be straight within ±8mm in any 5m section of wall, and the thickness of an individual bed joint should not vary by more than ±1.5mm from the average of the next eight successive joints. The chapter gives a worked example: eight joints totalling 84mm average 10.5mm, so the acceptable range for the next joint is 9mm to 12mm. Perpend (vertical) joints should not cumulatively displace in the same direction for more than five joints, and the centre line of any perpend should generally be within ±15mm of the next five successive perpends. Where a fair face can only be achieved on one side, such as on a half brick wall, the other face should be left neat and tidy.

Render

Render should be reasonably consistent in texture, finish and colour, flat within ±4mm vertically and horizontally in 5m, and free from crazing. The chapter defines crazing as a set of hairline cracks, generally less than 1mm deep and no more than 0.2mm wide. It also accepts that some localised hairline cracking is likely in both traditional and proprietary render, that colour may vary with background suction and the direction the wall faces, and that daywork joints and repairs may be visible but should not be unduly obtrusive. Areas close to features such as bell casts are excluded from the flatness tolerance.

Cladding and other external finishes

Unless the design specifies otherwise, curtain walling should be within ±2mm in any storey height or structural bay width and ±5mm overall, and rainscreen cladding within ±3mm in any storey height or bay width. Brick slip cladding should meet the same tolerances as fair faced masonry. Uncoated timber cladding will weather naturally, often to a silver or grey colour, and may weather unevenly where sills and roof overhangs shelter parts of the wall. Tile hanging should be reasonably uniform, particularly at abutments. Cast stone should be reasonably uniform in colour and texture, although efflorescence, fungal growth and colour variation may occur due to orientation, shading and pollution, and surface chips should be repaired to the manufacturer’s recommendations.

Internal walls and ceilings (Clause 9.1.3)

Plastered and dry-lined surfaces

Board joints should not be readily visible, and the surface should be within ±3mm measured with a 450mm straight edge with equal offsets. Surfaces are viewed from 2m in natural daylight with no artificial light shining on them. Some tooling marks may be visible in plastered walls and ceilings.

Walls

Walls should be reasonably uniform, although there may be minor textural differences around lights and other fittings. There should be no visible gaps between fittings and the wall, for example around switch plates, and jointing tape should be fully covered and unobtrusive. Walls should be flat within ±3mm measured with a 2m straight edge, applying in all directions, and no more than 8mm out of plumb for walls up to 3m high. Taller walls are limited to 8mm per storey and 12mm in total.

Ceilings

Ceilings should be level within 3mm per 1m for ceilings up to 6m across, measured between the furthest points. Ceilings over 6m across may be up to 20mm out of level. They should also be flat within ±5mm under a 2m straight edge.

Corners, boxings and duct casings

Corners, duct casings, access covers and their framing should be square, neat and tidy, and given an appropriate decorative finish. The chapter’s figures show a maximum deviation of ±5mm in 250mm for corner details and ±10mm from square in 500mm for boxings.

Cracking

This is one of the most frequently disputed areas. The chapter says some cracking up to 2mm wide may occur at wall, floor and ceiling junctions because of shrinkage and differential movement, and that small cracks may appear in wall finishes that pass across floors, such as staircase walls. Where stair strings meet a wall, a crack of up to 4mm may appear through shrinkage. Fine cracks at these junctions in the first year or two are therefore usually treated as normal. Cracks wider than these figures, cracks in unexpected places, or cracks that keep growing are worth reporting.

Skirtings

The gap between the floor finish (without coverings) and the bottom of the skirting should not exceed 5mm at completion, and skirting joints should look continuous when viewed from 2m in daylight. The chapter warns that the gap may increase through drying out, shrinkage or deflection, particularly with timber floors, and that gaps may appear at joints, at corners and between the wall and the skirting. Chapter 9.1 does not set separate tolerances for architraves; they are covered under paint finishes, which note that site-decorated trim may look different from factory-finished doors.

Doors and windows (Clause 9.1.4)

Internal window openings

Sills and window boards should be flat within ±3mm in every 2m. Heads and sills should be no more than 3mm out of level for openings up to 1.5m wide, or 5mm where wider, and reveals should be no more than 3mm out of plumb for openings up to 1.5m high, or 5mm where higher. Sills should be level within 3mm across their depth, measured from the frame, although tiled sills in bathrooms may be deliberately laid sloping away from the window. Reveals up to 250mm deep should be square to the window within ±5mm. Window frames should not be distorted in the opening and should be within 3mm of plumb up to 1.5m high, or 5mm when taller.

Internal doors

Internal doors and frames should be installed to the manufacturer’s recommendations and not be distorted in the opening. Frames should be within 5mm of plumb over their height and not out of plumb in two directions. The gap between the door and the head or jamb should be no more than 4mm and uniform, including at the meeting stiles of double doors. Distortion across a door is limited to 5mm in height and 3mm in width. The gap under the door to the unfinished floor should be between 10mm and 22mm, taking the building’s ventilation requirements into account. The chapter adds that homeowners will need to choose floor coverings to suit, or adjust the door height, and that in England and Wales, where the builder provides the floor finish, there should be a 10mm gap between the door and the floor finish for a 760mm wide door.

Fire doors and external doors

Fire doors should be installed to the manufacturer’s recommendations, and the tolerances apply without prejudice to ventilation and fire resistance. External doors and frames should be within 5mm of plumb without being out of plumb in two directions, with distortion limited to 5mm in height and 3mm in width.

Floors (Clause 9.1.5)

Floors should be level within 3mm per 1m for floors up to 6m across, measured between the furthest points across the full width. Floors over 6m across may be up to 20mm out of level. Floors should also be flat within ±5mm under a 2m straight edge. Underfloor service duct covers should be level with the adjacent floor finish, although drying shrinkage may cause minor differences in level, which can be more noticeable under thin floor coverings.

Glazing (Clause 9.1.6)

Glass should be free from undue defects. Viewed in daylight from inside the room at a minimum of 2m, or 3m for toughened, laminated or coated glass, the following are acceptable where they are not obtrusive or bunched: bubbles or blisters, hairlines or blobs, fine scratches no more than 25mm long, and minute particles. These rules do not apply within 6mm of the edge of the pane, where minor scratching may occur.

Tiling (Clause 9.1.7)

For ceramic, concrete, terrazzo and similar tiles, joints should be straight and in alignment unless the tiles are irregular by design. Unless the manufacturer specifies otherwise, wall tile joints should be at least 1.5mm for ceramic tiles, 2mm for smooth natural stone and 6mm for textured tiles, and floor tile joints should be at least 3mm, proportionally wider for larger tiles. Floor joints should generally not exceed the tile thickness, although joints of up to 10mm may be needed for tiles with dimensional irregularities. The tiled surface should be within ±3mm under a 2m straight edge, and lippage, the step between adjacent tiles, should be 1mm or less where the joint is up to 6mm wide, or 2mm or less where it is wider.

Kitchen units, worktops and fitted furniture (Clause 9.1.8)

Fitted furniture, including kitchen and bedroom units, doors and drawers, should be visually aligned vertically, horizontally and in plan, operate as the manufacturer intended, and have uniform gaps between adjacent doors and drawers where appropriate. There should be no significant differences in level where adjacent worktops meet. Factory-finished components should have no conspicuous abrasions or scratches when viewed in daylight from 0.5m, and abrasions caused during installation should be put right in line with the manufacturer’s recommendations, which may mean filling, polishing out, respraying or painting. Kitchen units should not delaminate, including those near hobs and extractor fans.

Two deliberate gaps in this clause are worth knowing about. No dimensional tolerance is set for gaps between adjacent doors and drawers or for their alignment, because adjustment is part of fitting. No dimensional tolerance is set for joins between adjacent worktops either, because of the variety of materials available. These items are judged by eye, against the standard of being visually aligned and uniform.

Sealants (Clause 9.1.9)

Sealant joints should look neat and tidy. They should be tooled to remove blisters and irregularities and to achieve a compact, smooth finish. Joints are viewed from 2m where possible, although the chapter recognises that showers and baths may make this impossible.

Paintwork and decoration (Clause 9.1.10)

Painted and varnished surfaces should be even in appearance and free from conspicuous runs and prominent brush marks. They should be reasonably smooth, free from nail holes, cracks and splits, have joints filled, and be reasonably uniform in colour, texture and finish. They are viewed in daylight from 2m, not by shining artificial light on the surface, with wall lights and uplighters switched off.

The chapter lists several things that are expected rather than defects: limited raised grain on timber, cracking of paint at joints caused by timber shrinkage, minor colour differences where paint has been touched up, external finishes dulling over time, resin bleeding from knots, and site-painted trim such as architraves and skirtings looking different from factory-finished doors.

Sanitary ware (Clause 9.1.11)

Baths, shower trays and basins should be free from scratches, chips and other damage at the time of handover, with no conspicuous abrasions, scratches or chips when viewed in daylight from 0.5m, or under the fixed lighting in rooms without daylight. The words “at the time of handover” matter. Report damage to sanitary ware at your pre-completion inspection or as soon as you move in, because months later it is hard to show that it was not caused after you took possession.

Other surfaces, roofs, garages and external works (Clauses 9.1.12 to 9.1.15)

Other surfaces and finishes, such as fascia boards, meter cabinets and radiators, should be reasonably smooth, free from nail holes, cracks and splits, have joints filled, and be reasonably uniform in colour, texture and finish.

Pitched roof tiles and slates should be reasonably uniform in texture, finish and colour, and suitably mixed to avoid excessive colour banding. Minor blemishes and variations on individual tiles are expected, and tiles with efflorescence when laid should be mixed to avoid a patchy appearance. Clause 9.1.16 points to the Roof Tile Association’s August 2023 guide on achieving the best visual effect with concrete and clay roof tiles.

Garage walls, floors and roofs should be built to appropriate tolerances. Cracks up to 2mm wide in unplastered garage blockwork may appear through thermal movement and shrinkage, garage floors may have falls for drainage or fire separation, unsealed floors may produce dust, and drying shrinkage may leave small gaps where the floor meets the walls.

Drives and paths should be within ±10mm under a 2m straight edge, although localised falls into gullies and channels are acceptable, and should be designed to minimise standing water. The chapter sets a clear, testable rule: one hour after rain has stopped, temporary standing water should be no deeper than 5mm and cover no more than 1m², and no standing water is permitted next to entrance doors. Drainage covers should align with the surrounding surface, with channel covers set slightly below it, allowing for future settlement.

Summary of key tolerances

What this means for homebuyers

Chapter 9.1 works in both directions. It gives you an objective, published benchmark, so you are not relying on a site manager’s opinion. It also tells you what is not a defect: fine shrinkage cracks at junctions, a skirting gap that opens as a timber floor dries, efflorescence on new brickwork, or a slight colour difference between factory-finished doors and site-painted architraves. Knowing both sides lets you concentrate on the issues most likely to be put right.

Many items are judged by appearance rather than measurement, using words such as “reasonably uniform”, “conspicuous” and “unduly obtrusive”. For these, follow the stated viewing conditions. If a mark is only visible with a torch held along the wall, it is unlikely to be accepted as a defect. If it is obvious from 2m in daylight with the lights off, it should be. Measurable items such as walls, floors, ceilings, doors and tiles can be checked with a 2m straight edge, a long spirit level and a set of feeler or tapered gauges.

Chapter 9.1 and snagging inspections

A professional snagging inspection is an independent check of a new home’s finish and workmanship before or shortly after completion. Chapter 9.1 is one of the key benchmarks a snagging inspector works to, because it is the same benchmark NHBC applies. A good snagging report does more than say “poor finish to hallway wall”. It records the location, includes a photograph and, where the item is measurable, gives the reading against the relevant tolerance. A finding such as “wall deviates 6mm under a 2m straight edge, exceeding the ±3mm tolerance in NHBC Chapter 9.1” is much harder for a builder to dismiss than a general complaint.

Timing matters too. The chapter is written to apply when the home is substantially complete and ready for NHBC’s pre-handover inspection, which is the same point at which a pre-completion snagging inspection takes place. Developers registered with the New Homes Quality Board must also allow buyers to have a suitably qualified inspector carry out a pre-completion inspection on their behalf, which is the ideal moment to record finishes against Chapter 9.1.

Using Chapter 9.1 when raising defects with your builder

Always report defects to your builder in writing and keep copies. For each item, give its location, include a clear photograph and, where possible, cite the clause and the figure, for example: “Clause 9.1.4: the gap between the bedroom 2 door and frame is 7mm at the head, exceeding the 4mm maximum.” For appearance-based items, state that you viewed the item under the conditions the chapter specifies. This shows you are applying NHBC’s own test, not a personal standard.

Expect your builder to point to the chapter’s softer provisions, especially that acceptability is in NHBC’s opinion and that remedies should be proportionate. That is legitimate, but it works both ways. The chapter itself says it is not intended to deal with every situation, so a finish can be within a numerical tolerance and still be unacceptable because of how visible or extensive it is. Proportionality can argue for a repair as well as against one.

If your builder will not deal with a reported defect during the two-year builder warranty period, you can ask NHBC to step in through its resolution service, and NHBC uses Chapter 9.1 when doing so. If your developer is registered with the New Homes Quality Board, you may also be able to refer an unresolved complaint to the New Homes Ombudsman Service. A complaint raised within the first two years after completion can be referred after 56 days, even if the referral itself is made after the two years have ended.

Limitations to understand

Guidance, not a contract. NHBC produces the Standards as guidance for its builder customers on its warranty requirements. Its disclaimer states that they do not constitute advice, are not to be relied upon by third parties and do not create any legal or contractual relationship. Chapter 9.1 carries great weight in a dispute, but it is not, by itself, a contract between you and your builder.

The builder is responsible in the first two years. During the first two years of Buildmark, the builder is responsible for putting right defects caused by failing to meet NHBC’s requirements, with NHBC’s resolution service behind them. This is when cosmetic finish issues are most realistically resolved.

Cosmetic versus structural. From year three to year ten, Buildmark is an insurance policy covering physical damage caused by defects in specified parts of the home, mainly the structure. Cosmetic issues such as paint finish, minor plaster blemishes, tile alignment or a small worktop scratch are very unlikely to be covered then, which is why it pays to report finish defects early.

Discretion and judgement. Some items, such as gaps between kitchen doors and drawers or joins between worktops, have no dimensional tolerance at all. Others rely on words like “reasonably” and “conspicuous”, and final judgement on appearance rests with NHBC.

Other warranty providers. Chapter 9.1 applies to NHBC-registered homes. If your home is covered by another warranty provider, that provider’s own technical manual applies, although many use very similar tolerances.

Frequently asked questions

My builder says a defect is “within tolerance”. Does that mean I have no case?

Not necessarily. Check that the item was actually measured, and measured correctly, for example with a 2m straight edge for wall flatness rather than a short spirit level. Many appearance-based items are judged by viewing conditions rather than numbers, and the chapter says discretion should be exercised, so a highly visible or extensive issue can still justify a repair.

Can I use a torch to show my builder a defect in the plaster?

You can, but it will not help much. Chapter 9.1 says walls, ceilings and paintwork should be viewed from 2m in natural daylight with no artificial light shining on the surface. A blemish that only shows under a torch is unlikely to be accepted as a defect.

Are cracks in my new home a problem?

Fine cracks up to 2mm wide at wall, floor and ceiling junctions, and up to 4mm where stair strings meet a wall, are described in the chapter as likely results of shrinkage. Wider cracks, diagonal cracks across walls, or cracks that keep growing should be reported and may need further investigation.

How big a gap under my internal doors is acceptable?

Between 10mm and 22mm to the unfinished floor, taking ventilation into account. In England and Wales, where the builder provides the floor finish, there should be a 10mm gap between the door and the floor finish for a 760mm wide door.

Which edition of the Standards applies to my home?

The edition in force when your home’s foundations were begun. The 2026 edition applies to NHBC-registered homes whose foundations were begun on or after 1 January 2026.