Understanding Use Class 4 (UC4)

Understanding Use Class 4 (UC4)

Date Published

21 September 2021

Document Type





Consumer and contract law require that any product offered for sale must be fit for its intended use and a wood product impregnated with preservative is no exception.

The minimum standards for the treatment of wood are set out in British Standard BS8417 (Preservation of Wood: Code of Practice). In this standard, the level of treatment is tailored to the application ‘Use Class’ of a wood product as defined in BS EN 335 (Durability of wood and wood-based products).

Use Class 4 is for end uses where wood is in contact with or very close to the ground and frequently wet.

Case studies

Streatham & Clapham High School, a successful independent day school for girls, has been transformed and upgraded by Cottrell and Vermeulen Architecture.

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