Structural timber allowed for buildings between 11m and 18m in height

The newly published Update to Approved Document B from the Department of Levelling Up, Housing and Communities, has ruled that structural timber is approved for use within the external walls of buildings between 11 and 18 metres.

It had originally proposed extending the combustibles ban from 18m in height down to 11m, which would have had an impact on structural timber use in taller buildings.

The government’s decision was in line with the response from the timber industry, led by the Confederation of Timber Industries working with partners including ACAN, which called for the government to take a risk-based approach, and to focus restrictions on “cladding rather than structure”.

In buildings that include a ‘residential’ purpose with 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.

All the details and changes, which come into force on December 1, 2022, can be accessed here 

“We recognise the potential environmental benefits of timber construction where it can be used safely,” the Government said.

“The case for exempting structural timber from the requirements of the ban in the highest risk buildings (above 18 metres) has been made by some respondents. The government is not yet satisfied that the case is strong enough to justify an exemption at this time.

“The Department has commissioned research to look at the issue and how the use of modern methods of construction will inform the development of building regulations and any other necessary action.

“The government is committed, through the England Tree Action Plan to increase the use of timber in construction and we are working across government to identify key opportunities for the safe growth of timber use in low-rise buildings.”

Timber Development UK (TDUK) chief executive David Hopkins said blanket bans had caused damage and legislative confusion in the past

“We have been working with a wide range of stakeholders, including politicians, councils, leading architects, and others to shift the debate on these issues, so this result is hugely encouraging,” he said.

However, it is just the first step, and we are focused on opening the market to timber systems and products which are proven to be safe, reliable and efficient.

“We would like to thank the government for working with industry over these past few months and taking a more active interest in timber construction. We hope this latest ruling is the first of many steps toward a low-carbon future in construction.”