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External Timber Cladding and Fire Risk
Guidance to Amended Building Regulations

July 2022

WPA Guidance Note FR5

Recently published amendments to Approved Document B of the Building Regulations confirm that, in buildings with a ‘residential’ purpose and a storey of 11m or more in height, elements such as cladding, balconies, and other external surfaces must achieve class A1 or A2-s1, d0.

While some exemptions apply, this effectively bans the use of combustible materials for these elements.

Timber cladding is still approved for most non-residential buildings and for all those under 11m in height, often with the added protection of flame retardant treatment. 


For ‘RELEVANT’ Buildings (residential multi-storey 18m+)

  • No timber cladding on buildings over 11m, but you can use timber within the external wall structure up to 18m.

  • No timber in external walls on buildings above 18m – this affects external wall framing/CLT and cladding.


Other Buildings (non-residential other than domestic housing)

  • No change to before – timber cladding can be used, normally with Flame Retardant (FR) treatment, up to and beyond 18m

These changes to the Building Regulations will come into force on 1 December 2022. 

To reflect these changes and guide members through the implications for their business, the WPA has updated Guidance Note FR5: External Timber Cladding and Fire Risk – Guidance to Amended Building Regulations.

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