Introduction

2.1The Standards and Technical Requirements

Application of the Standards

The NHBC Standards contain the Technical Requirements, performance standards and guidance for the design and construction of homes acceptable to NHBC. The home is defined in NHBC Rules for builders and developers registered with NHBC.
The Standards come into effect for every NHBC registered home whose foundations are begun on or after 1 January 2018, and they apply throughout the UK, unless otherwise stated.

Composition of the Standards

The Standards are divided into 10 Parts, each covering a particular element and subdivided into chapters which, in principle, follow the normal build sequence (the list of chapters is shown in the Contents section of Part 1). The front cover of each chapter contains its scope, together with a list of its contents

Technical Requirements

The Technical Requirements are shown in red text in this chapter, and must be met by the builder.

Performance standards

The performance standards support the Technical Requirements and are shown in bold black text backed with a shaded box.
Where the performance standards are followed, the Technical Requirements for that particular item of work will be met.
Alternative standards of performance will be acceptable only if, in the opinion of NHBC, the Technical Requirements for that particular item of work are met and the standard achieved is not lower than the stated performance standard.

Guidance

Guidance on how the performance standard may be met is shown in black text and is based on normal construction procedures and recommended practices which have been shown to be satisfactory and acceptable over time. NHBC will consider alternative methods to meet specific requirements, subject to prior consultation and evaluation.

Guidance is also contained in illustrations and digital 3D models.

Guidance is provided to demonstrate specific technical principles, and should not be used as working construction details.

Limitations on use

The Technical Requirements, performance standards and guidance form acceptable technical benchmarks for a particular item of work, but do not form a complete specification and should not be used as such in contracts. Individual chapters cover, as far as practical, the requirements for particular elements of construction. To avoid repetition, some cross-referencing is made between chapters.

The NHBC Standards do not apply to:

Such matters are covered by statutory requirements.

Interpretation

Where a difference exists in how to interpret the Technical Requirements, performance standards and guidance, this would generally be resolved by further consultation, failing which, NHBC will exercise its right to decide in accordance with the NHBC Rules.

Testing

Where required, samples of materials, products and systems shall be tested in accordance with Technical Requirement R3 and the NHBC Rules.

Standards and codes of practice

Where NHBC Standards refer to authoritative documents such as British Standards, the documents shall be the editions current at the time of Building Regulation approval, unless other recommendations are agreed by NHBC in writing.

The standards referred to in the NHBC Standards comprise specifications, codes of practice and published documents that are published by BSI, the European Committee for Standardization (CEN) and the International Organization for Standardization (ISO).

Tolerances

All work shall be within acceptable tolerances. Where applicable, account should be taken of Chapter 9.1 ‘A consistent approach to finishes’. In other situations, tolerances will be those currently acceptable in the house-building industry.

Acknowledgements

NHBC is indebted to members of the Standards Committee, the Standards Review Group, the Scottish Technical Subcommittee and the Northern Ireland Technical Subcommittee for their work in developing and maintaining the NHBC Standards.

NHBC also wishes to acknowledge the help given by consultants, authoritative organisations, individuals and staff.

Technical Requirements

R1 Statutory 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.

R2 Design requirement

Account shall be taken of:

a) The land quality, including

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:

c) The geographical location of the site, including:

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.

R3 Materials requirement

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:

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:

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, e.g. 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.

R4 Workmanship requirement

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:

R5 Structural design requirement

The following shall be designed by Chartered Civil or Structural Engineers 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:

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

The Builder shall:

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

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