With the ban set to prevent the use of cross laminated timber (CLT) in high rise residential construction, some within the sector have criticised the government’s plans.
In a release last week, the government confirmed the ban that it had announced in the summer on combustible material use in new high rise buildings, with regulations laid out in parliament today that will ‘give legal effect’ to the ban. Combustible materials will not be permitted on external walls of new buildings 18m tall or higher that contain flats, hospitals, residential care premises, boarding school dormitories or student accommodation.
Schools that are over 18m in height and built as part of the government’s centrally delivered build programmes will also not use combustible materials on external walls. Dezeen reported that the ban would ‘limit the use of’ CLT in construction, as it limits the use of materials to those with a European fire rating of Class A1 or A2, while stating ‘explicitly’ that wood products ‘do not come under this classification’.
The government’s document states that ‘the policy prohibits the use of timber materials in the external wall of buildings within the scope’, with the news outlet noting that CLT is ‘increasingly being championed in architecture as a sustainable alternative to steel and concrete structural frameworks’. The document added that ‘engineered timber offers an alternative to traditional methods of construction in buildings within the scope of the policy. It is therefore likely to slow down the use of engineered timber in future development in the medium to long term’.
In response, one of the ‘leading pioneers’ of CLT construction in the UK, Waugh Thistleton Architects, expressed ‘disappointment’ in the ban and said that the government has ‘overreached its stated aim’ with regards to fire safety. The organisation stated: ‘We are clear that mass timber construction is not a valid target for this change and will continue to advocate for its exemption. The UK is a world leader in the development of engineered timber construction with over 500 buildings completed.
‘As the government acknowledges this change in regulations will have an impact on the continued innovation and development of low carbon construction, and hence on the rate at which the construction industry can tackle climate change.’
The company also said that the statement from the government demonstrated a ‘misunderstanding’ of the fire performance of engineered timber, but made clear that the government ‘is not proposing a ban on using CLT, but a different approach to building tall residential structures’.