BS 8417:2024

This British Standard gives recommendations and guidance for the preservative treatment of wood to provide protection against biodeterioration in end-use situations. It gives recommendations for determining the need for treatment and for specifying the type of treatment.

This British Standard also recommends levels for the penetration and retention requirements of preservatives tested to BS EN 599‑1 and creosote preservatives, using the terminology in BS EN 351‑1, for different timber components. It also takes into account the natural durability and treatability of the wood employed, the use class as defined in BS EN 335 and the desired service life. It also provides guidance on establishing whether a specified level of treatment has been achieved.

This British Standard does not include precise treatment parameters to achieve the recommended penetrations and retentions.

NOTE 1: It is the responsibility of the treater to use wood in an appropriate condition and to use an appropriate treatment schedule to achieve the recommended values of penetration and retention.

This British Standard applies to solid wood and glued laminated wood (Glulam).

This British Standard does not apply to:
a) wood-based panel products;
NOTE 2: Guidance on treatment is given in the Wood Protection Association Guidance note TW 15 [3].
b) wood that has been modified by physical, biological or non-biocidal chemical techniques in order to enhance its performance; or
NOTE 3: Guidance on cross-laminated timber (CLT) is given in Annex A.
c) curative treatments.

NOTE 4: Only preservatives approved under the Control of Pesticides Regulations 1986 (as amended) [4] or authorized in Great Britain under The Chemicals (Health and Safety) and Genetically Modified Organisms (Contained Use) (Amendment etc.) (EU Exit) Regulations 2020 [5] or (in Northern Ireland) under the Biocidal Products Regulation [6] are permitted for the treatment of wood in the United Kingdom.