When purchasing a new build home, the quality of your floor finishes plays a significant role in how the property looks, feels, and performs over time. The NHBC Standards 2026, Chapter 9.3, sets out the technical requirements that builders must follow when installing floor finishes. This guide explains each section of the standard in plain terms, so you know what to expect and what to look out for.

At New Build Inspections, our snagging inspectors are trained to assess floor finishes against these standards. While a snagging inspection is not a full structural survey, it does include a thorough visual and practical assessment of your flooring to identify defects, poor workmanship, and areas of non-compliance that your developer should put right.

9.3.1 Compliance

All floor finishes in your new build home must comply with the NHBC Technical Requirements. This means that the flooring, whether it is screed, tiles, wood, or any other type of finish, should be installed to the standards set out in this chapter. The guidance also cross-references several other chapters relating to substructure, suspended floors, upper floors, and light steel framing, so the standards are designed to work together to ensure your home is built correctly from the ground up.

9.3.2 Provision of Information

Before any floor finish work begins, the builder is expected to produce clear designs and specifications and distribute them to the relevant tradespeople on site. This should include details such as the schedule of finishes, screed thickness and mix, sound insulation details, the extent of tiled surfaces, the location of services near tiles, and staircase finish details. This requirement exists to reduce errors on site, as poor communication between trades is a common source of defects in new builds.

9.3.3 Insulation

Thermal and acoustic insulation beneath or within your floor finishes must provide appropriate performance and be suitable for where it is being used. The standards specify several acceptable insulation materials, including expanded polystyrene (EPS), rigid polyurethane (PUR), rigid polyisocyanurate (PIR), and fibre building board, each to their relevant British Standard. Proprietary products may also be used provided they have been assessed in accordance with NHBC Technical Requirement R3. If your home has underfloor heating or separating floors between dwellings, getting the insulation right is especially important for both energy efficiency and noise control.

9.3.4 Screed

Non-structural floor screeds must be adequate for their location and intended use, and they must provide a suitable background for whatever floor finish will go on top. The standard addresses three key areas: installation, thickness, and screed over insulation.

9.3.4.1 Installation

Before screeding takes place, surfaces should be clean, free of debris, and suitably prepared to provide an adequate mechanical key. Damp proofing must be completed before screeding starts. The standard also notes that screeding should not be carried out in adverse weather conditions. In hot or dry weather, precautions should be taken to stop the surface drying out too quickly, and in cold weather, screeds should not be installed at all. Any screed damaged by cold must be removed and replaced.

Non-structural screeds should be installed to the specified thickness and provide an even surface. The sand to cement mix is generally between 1:3 and 1:4.5, and where the screed is deeper than 40mm, concrete may be used instead. Where services such as underfloor heating pipes are bedded in the screed, there should be a minimum 25mm of cover over the highest point of the pipes and insulation, and provision must be made for thermal movement.

Where underfloor heating is present, the non-structural screed should be sub-divided into bays not exceeding 40m², with a maximum length of 8m, or installed per room. Expansion joints must be consistent with those in the substructure and provided between independently controlled heating zones.

9.3.4.2 Non-Structural Screed Thickness

The NHBC standard specifies minimum thicknesses for cement and sand screeds depending on how they are laid. The table below summarises the requirements:

9.3.4.3 Screed Over Insulation

Where screed is laid over insulation, the screed should be reinforced, and the insulation must provide adequate compressive strength to support both the wet screed and the finished floor loads. The insulation should be tightly butted and, where required, turned up at perimeters to prevent thermal bridging. A separating membrane must be placed between the insulation and the screed, with joints lapped, taped, and turned up at the perimeter. Sound insulating floating floors must also comply with the relevant Building Regulations.

9.3.5 Ceramic, Concrete, Terrazzo and Similar Tile Finishes

Tile flooring must provide a suitable wearing surface for its location and intended use. Before tiling begins, the substrate must be sufficiently dry, which generally means allowing six weeks for concrete bases and three weeks for screed. The substrate should also be reasonably true and flat to within plus or minus 3mm when checked with a 2m straight edge. The surface must be clean and free from laitance, dirt, dust, grease, and anything incompatible with the adhesive.

Where a calcium sulphate (anhydrite) screed has been used, it requires particular attention. These screeds must be allowed to dry at a specific rate, and the moisture content should not exceed 75% relative humidity before tiling begins. The weak layer of laitance that forms on the surface must be removed, and the screed should be sealed with an appropriate primer. In areas likely to be exposed to occasional wetting, such as where a bath or shower is present, an intermediate waterproofing layer (tanking system) should be applied before tiling.

When tiles are installed, they should be bedded on a solid bed of mortar or proprietary adhesive, arranged to minimise cutting, and laid with straight, neat joints of even width, with a minimum 3mm joint unless the manufacturer specifies otherwise. Where tiles are fixed to a wood-based substrate, the floor must be designed to take the additional load, and tiles should be bedded with a deformable (flexible) tile adhesive such as C2S1, with water-resistant grout.

Movement joints are an important part of any tiled installation. They should be provided around the floor perimeter and at rigid upstands where tiled areas are wider than 2m, and used to separate bays at 8–10m centres. Where underfloor heating is present, the floor area should be divided by intermediate movement joints into bays no greater than 40m² with an edge length not exceeding 8m. Grout should be cement-based epoxy resin or a proprietary product, and should be water-resistant in areas where tiles may become saturated.

Tile defects are among the most common issues found during snagging inspections. Our inspectors look for uneven tiles, hollow spots (which indicate poor adhesion), cracked or chipped tiles, inconsistent grout lines, and missing or inadequate movement joints.

9.3.6 Wood Finishes

Wood and wood-based flooring must provide a suitable wearing surface for the location and intended use. The standard covers thermal insulation and damp-proof membranes (DPMs), sound insulation, condition of the substrate, directly applied finishes such as wood blocks and parquet, and indirectly applied finishes such as softwood boarding and wood-based panel products.

9.3.6.1 Thermal Insulation and DPMs

Where insulation is positioned above an in-situ concrete slab, a DPM is required. Where insulation sits above a dry, precast system, a DPM may, in certain circumstances, be omitted. Proprietary insulated flooring must comply with Technical Requirement R3 and the manufacturer’s recommendations regarding vapour control layers and DPMs. Getting this right is essential to prevent moisture damage to your flooring over time.

9.3.6.2 Sound Insulation

Floating floor finishes should be designed to isolate the floor finish from the supporting floor and walls, avoid excessive movement or squeaking, avoid the use of fixings that penetrate the insulation layer, and ensure there are no air paths, especially at the perimeter. Where flooring is installed on a resilient material on a separating floor, edges should be isolated from walls and skirtings by a resilient layer. If the floor relies on a soft covering to meet the minimum sound insulation standard, that covering should be permanently fixed in position.

9.3.6.3 Condition of the Substrate

Screeds or concrete receiving wood flooring should be dry, with moisture content tested and found suitable in accordance with BS 8201. Generally, screeds need around two months to cure for a 50mm thickness, and concrete slabs need approximately six months. The substrate should be free from high spots, nibs, and major irregularities, with differences in level dubbed out. A DPM and/or air and vapour control layer should be incorporated to protect the wood finishes, taking care not to trap moisture between layers.

9.3.6.4 Directly Applied Finishes

Directly applied finishes such as wood blocks, parquet, and wood mosaic should be installed in accordance with the manufacturer’s recommendations, using the correct adhesives spread evenly. They should be laid according to the specified pattern with gaps left around the perimeter to allow for movement. Screed or concrete surfaces should be treated with a suitable primer before adhesive is applied.

9.3.6.5 Indirectly Applied Finishes

Indirectly applied finishes such as softwood boarding and wood-based panels should be installed with air and vapour control layers where required, using preservative-treated battens. Provision should be made to support heavy items such as storage heaters and boilers, and battens must be fixed to prevent excessive movement. The standard specifies maximum batten spacing depending on the type and thickness of the finish material. For example, 18mm P5 chipboard requires battens at no more than 450mm centres, while 22mm chipboard can span up to 600mm centres.

9.3.7 Flexible Sheet and Flexible Tile Finishes

Flexible sheet and tile finishes, such as vinyl flooring, must provide a suitable wearing surface and be installed in accordance with the manufacturer’s recommendations. They should generally be fully bonded and laid on an even backing surface without high spots or cracks. Where necessary, a fabricated underlay of an appropriate type and thickness should be used. The finished surface should be reasonably level and smooth, particularly at doorways and junctions, and fitted with skirtings, coves, and coverstrips where required.

The standard specifies that flexible sheet flooring materials should not be exposed to temperatures below 18°C for 24 hours before or during laying, and that the substrate must be sufficiently dry. Where flexible flooring is installed on ground-bearing concrete floors, a DPM should be incorporated to prevent rising moisture from adversely affecting the finish. During installation, adhesives should be spread evenly, surfaces pressed down firmly to prevent curling or bubbling, and surplus adhesive removed.

During a snagging inspection, our inspectors will check for issues such as lifting edges, bubbling, uneven surfaces, visible joins, and poor cutting around fittings and pipes.

9.3.8 Asphalt Finishes

Mastic asphalt floor finishes, where used, must be suitable for their intended location and purpose. They should be designed and constructed in accordance with BS 8204-5, be either Grade I or II, and 15–20mm thick. When used as an underlay for other finishes, asphalt should be applied as a single coat. This type of finish is less commonly encountered in typical new build homes but may be present in some communal or commercial areas.

9.3.9 Staircase Finishes

Staircase finishes must permit safe usage and be suitable for their intended use. An important requirement is that the rise and going of each step should remain uniform after the application of any staircase finish, including at the top and bottom of the flight. Inconsistent step dimensions are a safety hazard, and this is something our snagging inspectors pay close attention to. For communal stairs, such as escape routes in blocks of flats, non-slip nosings or inserts should be provided where specified and fixed in accordance with the manufacturer’s recommendations.

9.3.10 Further Information

The NHBC Standards reference several further publications for additional guidance, including BS 5250:2021 (Management of moisture in buildings) and BRE Report BR 262 (Thermal insulation: avoiding risks, 3rd Edition). These documents provide more detailed technical guidance on managing moisture and insulation risks in buildings.

How New Build Inspections Can Help

Understanding the NHBC Standards can feel overwhelming, but you do not need to be an expert. That is what our professional snagging inspectors are for. When we inspect your new build home, we carry out a thorough assessment of all visible floor finishes, checking for defects in screeds, tiles, wood flooring, vinyl, and staircase finishes. While our snagging inspections are not a substitute for a full structural survey, they are specifically designed to identify the kinds of defects and poor workmanship that are covered by these standards.

We provide a detailed snagging report and support you in getting your developer to put things right. Our aftercare service means we are with you beyond the inspection itself, helping to ensure that your new home’s floor finishes, and everything else, meet the quality standards you are entitled to expect.