The RIBA has joined campaigners calling for structural timber to be excluded from an extension of the combustible cladding ban
Combustible materials, including timber, face being banned from the exterior walls of new residential buildings over 11m in England and Wales under plans put out for consultation by the government in January.
The proposal has met opposition from architects, who point out it would effectively ban the use of structural timber for residential buildings – including care homes, student digs and hospitals – over three-storeys tall.
Now the RIBA has revealed it urged the government ‘not to include the primary structure of the building’ in the combustible materials ban when it responded to the consultation, which closed yesterday (25 May). This would mean structural timber could still be used in the external walls.
The RIBA also called on the government to carry out further research into the fire performance of structural timber when subject to real fire loads, so that ‘the construction industry might benefit from the lower embodied carbon benefits’ provided by using the material.
Jane Duncan, chair of RIBA’s advisory group on fire safety, said the government should provide clear guidance and fund research ‘to ensure innovation can still take place to combat and the climate crisis’.
The RIBA’s call comes after campaign group Architects’ Climate Action Network (ACAN) and architects including AHMM, dRMM and Glenn Howells, urged the government not to ban structural timber in any form.
Anthony Thistleton, co-founder of Waugh Thistleton, said he was pleased RIBA has differentiated between structural timber and cladding.
‘The ban has implied that the material, in itself, increases fire risk which is not the case. We know how to build tall, fire-safe residential buildings using CLT,’ he said.
ACAN also welcomed the RIBA’s response, saying that it was ‘a significant evolution in their language around this issue from August 2018’.
It also said that ‘greatly improved testing methodologies’ for structural timber would ‘clear the way for its use on a meaningful scale in UK construction’, adding: ‘This is paramount to our ability to decarbonise industry.’
Elsewhere in its response to the consultation, the RIBA urged the government to extend its 2018 combustible cladding ban to include hotels, hostels and boarding houses as well residential buildings – but said it should only apply to ‘key materials’ in external walls.
It also cautiously supported lowering the height threshold for the ban from 18m to ‘any relevant building with a storey over 11m’, but said further research should be done to determine the appropriate height.