NHBC Standards 2006

2.3 Timber preservation (natural solid timber)


2.3 - M1Materials standards

2.3 - M1

All materials shall:
(a) comply with the Technical Requirements
(b) take account of the design


Materials that comply with the design and the guidance given in Appendix 2.3-A will be acceptable for timber preservation.

The specification should state the specific treatment and standard required.

Preservative treatments should comply with all relevant standards and Codes of Practice. Proprietary treatments not contained in this Chapter or in British Standards should comply with Technical Requirement R3 (see Chapter 1.1 'Introduction to the Standards and Technical Requirements').

In all cases, preservatives must meet the requirements of the Control of Pesticides Regulations (1986) administered by the Health and Safety Executive.

The safety instructions published by the manufacturers should be followed.

References to British Standards and Codes of Practice include those made under the Construction Products Directive (89/106/EEC) and, in particular, appropriate European Technical Specifications approved by a European Committee for Standardisation (CEN).

Where copper/chromium containing preservatives (CC, CCP or CCB) have been used, it is important that metal fittings are not applied to the timber until the salts of the treatment have been "fixed" (7-14 days). In situations where occasional dampness is expected, metal fittings in contact with timber treated with copper containing preservatives should be galvanized. Where timber treated with copper containing preservatives is likely to become wet, fittings of austenitic stainless steel should be used.