NHBC 2025 Technical Requirements

NHBC will generally accept work that accords with relevant Building Regulations/Building Standards and supporting documents. Exceptions would be where NHBC has a higher standard. 

Account shall be taken of: 
a) The land quality, including 

     i) climate 

     ii) topography 

     iii) geology and ground conditions 

     iv) contamination 

     v) workings below ground 

     vi) previous use of the site 

     vii) any other aspect, on or adjacent to the site, could affect the design. Where appropriate, the land quality will have to be determined by a person acceptable to NHBC. 

b) The structural adequacy of the works. The design, with appropriate factors of safety, shall satisfactorily allow for loads during and after construction and for their transfer to the supporting structure, or foundation, without undue movement, including: 

     i) self weight 

     ii) all imposed loads, including wind loads 

     iii) construction loads.

c) The geographical location of the site, including: 

     i) exposure to wind and rain 

     ii) topography. 

d) the position of the dwelling on the site, especially with reference to the dwelling’s exposure to the weather, including at early stages in the development of a site, even if it is eventually protected by structures built later. 

e) the position of building elements within the construction works, including the interrelationship of materials and constructions. 

f) the security of the dwellings. 

The structure of the home shall, unless specifically agreed otherwise in writing with NHBC, have a life of at least 60 years. 

Individual components and assemblies, not integral to the structure, may have a lesser durability and need planned maintenance, repair or replacement during that period. 

Account shall be taken of the use and location of materials, products and building systems in relation to: 

• durability of both the structure and individual components and assemblies 
• geographical location 
• position on the site 
• position within the structure. 

Materials, products and building systems will normally be acceptable if they comply with the following: 

a) Materials and products used for critical functions 
Functions critical to performance are: structure, fire resistance, weatherproofing, durability, thermal and sound insulation, services including heating appliances and flues. Any of the following are acceptable:

     i) performance in accordance with standards set by NHBC, or 

     ii) where no NHBC standard is set, compliance with the relevant British Standard or equivalent European Technical Specification approved by a Committee for Standardisation, provided they are used in accordance with the relevant Code of Practice, or 

     iii) compliance with standards not lower than those defined in a relevant British Standard specification or equivalent, provided their use is accepted by NHBC, or 

     iv) satisfactory assessment by an appropriate independent technical approvals authority accepted by NHBC, or 

     v) use of materials and products in accordance with well established satisfactory custom and practice, provided that such custom and practice is acceptable to NHBC, or 

     vi) acceptance, in writing, by NHBC Accepts. 

b) Materials and products used for non-critical functions 
Compliance with the above acceptance criteria for critical functions or strictly in accordance with manufacturers’ recommendations for the specific use. 

c) Reclaimed materials 
Reclaimed materials may only be reused with the prior agreement of NHBC. Independent certification of suitability may be required. 

d) Proprietary building systems 
Reference should be made to R3a iv. 

e) Timber durability 
Reference should be made to Chapter 3.3 ‘Timber preservation (natural solid timber)’. 

f) Recovered aggregates 
Aggregates derived from recovered inert waste, eg recycled aggregate, should only be used where it can be demonstrated that the inert waste material has been fully recovered, has ceased to be a waste as defined by the Waste Framework Directive 2008 and has become a product. To this end, recovered aggregates produced by a supplier complying with a recognised defined quality management scheme such as the WRAP Quality Protocol and meeting end-of-waste criteria, will be acceptable to NHBC. 

Note(s) 
Equivalents to British Standards or technical approvals authority shall be those accepted in the UK. 

The Builder shall ensure that: 

a) the conditions of the materials, products and the completed work are satisfactory 

b) appropriate precautions are taken to prevent damage 

c) account is taken of the following:

     i) the requirements of the design 

     ii) suitable methods of unloading and handling 

     iii) proper protection during storage 

     iv) use of correct installation methods 

     v) protection against weather during construction (including excessive heat, cold, wetting or drying) 

     vi) protection against damage by following trades. 

The following shall be designed by Chartered Civil or Structural Engineers whose status (including professional indemnity insurance) is accepted by NHBC:

1. foundations on hazardous ground where the hazard makes special consideration necessary. (Note: This would not apply to matters for which NHBC sets standards, such as building near trees, except where specified to the contrary)
2. foundations and superstructure of every building over three storeys in height
3. certain types of foundations and retaining walls, as required in the individual chapters of the NHBC Standards
4. any structural element which is not based on specific design criteria as laid down in the chapters of the NHBC Standards
5. any dwelling not constructed in accordance with UK traditional practice.

Note(s)

Other structural elements may be designed by a Chartered Civil or Structural Engineer or others whose status (including professional indemnity insurance) is accepted by NHBC.

The structural design shall take account of the durability requirement in Technical Requirement R3 Materials.

In England, Wales, Northern Ireland and the Isle of Man, structural design may be undertaken by the Builder’s own Engineer or a Consulting Engineer employed by the Builder. Where specialist subcontractors undertake the design, it must be separately appraised by the Builder’s own Engineer or by a Consulting Engineer employed by the Builder to ensure that the site investigation, choice of foundations, siting and construction of dwellings are properly taken into account and that the design is appropriate for the loading and conditions.

In Scotland, the Engineer shall be independent of the Builder and specialist subcontractor.

Account shall be taken of all parts of the following British Standards:

• Eurocodes and their respective National Annexes
• BS EN 1990. Eurocode 0: ‘Basis of structural design’
• BS EN 1991. Eurocode 1: ‘Actions on structures’
• BS EN 1992. Eurocode 2: ‘Design of concrete structures’
• BS EN 1993. Eurocode 3: ‘Design of steel structures’
• BS EN 1995. Eurocode 5: ‘Design of timber structures’
• BS EN 1996. Eurocode 6: ‘Design of masonry structures’
• BS EN 1997. Eurocode 7: ‘Geotechnical design’.

Alternatively, designs in accordance with BS 8103 ‘Structural design of low rise buildings’ will be acceptable.

The Builder shall:

• require the Engineer to issue clear instructions for site personnel
• not permit departure from the design without the Engineer’s written consent
• require the Engineer or their representative to carry out such inspections as may be required by NHBC to ensure the adequacy of the design and construction.

The Builder shall ensure that the Engineer visits the site during construction:

• when the foundations have been designed under this Technical Requirement, or
• when specifically required by NHBC in these Standards.

The Engineer shall be satisfied that the design is suitable for the conditions encountered on the site of each dwelling. When requested by NHBC, the Builder shall:

• produce such design documents, calculations and prescribed forms of certification as NHBC requires for scrutiny
• provide design documents and assembly instructions, solely for the use of NHBC staff
• arrange for NHBC staff to have access to places where off-site fabrication is taking place.