In 2009, Waugh Thistleton Architects oversaw the completion of Murray Grove, a nine-storey residential block in Hackney with a superstructure of cross-laminated timber (CLT).
It was hailed as the world’s tallest timber residential building and as a game changer for engineered timber as a safe and viable alternative to concrete and steel for mid-rise, or even higher, residential buildings. Other successful CLT residential projects duly followed.
However, since the exemplar project in Murray Grove and those that succeeded it, many argue that structural timber became a perceived risk in the post-Grenfell legislative review. In 2022 the Department of Levelling Up, Housing and Communities ruled – after a period of consultation - that structural timber was approved for use within the external walls of buildings between 11 and 18 metres.
As the profession continues to discuss viable, sustainable alternatives to concrete and steel - and how to meet its climate and sustainability goals - using structural timber has once again become a focal topic. So much so, the task of de-risking the material and changing perception both inside and out of the profession is well under way.
What guidance is available to architects for using structural timber?
The National Federation of Builders’ Carbon Report of 2020 says that the construction industry represented 10% of total UK carbon emissions and contributed to a further 47% directly. Currently, timber offers a lower carbon solution than either concrete or steel, providing an opportunity to be carbon negative over a 50-year cycle.
No wonder there is a growing movement that argues using structural timber in larger buildings is a viable, sustainable option to help cut emissions and reach net zero carbon goals. Especially if that approach is allied to ethical forestry and timber sourcing to match increased demand and safeguard the future of timber as a material.
Founder and Director of Waugh Thistleton, Anthony Thistleton-Smith, says there is a huge appetite to building in timber, both among UK housing providers and in overseas markets. And not just for the carbon savings – further potential advantages include speed of construction, safety with deliveries, impact on local environments and - in his opinion - higher quality buildings.
Allied to this apparent appetite on the ground are resources for architects, who are urged to consider engineered timber structures in their design stages.
The government has a timber in construction roadmap – which RIBA fed into the development of - that is actively promoting greater domestic supply and uptake of mass engineered timber; including in mid-rise commercial buildings and non-residential buildings.
The direction of travel is clear, says Anthony, and industry bodies such as the Structural Timber Association and Timber Development UK are excited about the prospects for investment and industry take-up.
The Royal Institute of Chartered Surveyors (RICS) also talks at length about timber and carbon sequestration in its ‘Whole life carbon assessment for the Built Environment’ professional statement.
Moreover, a forthcoming event at RIBA, 66 Portland Place, London (2 July 2024), Navigating structural timber construction to address Net Zero, will bring together leading advocates for structural timber design. Anthony will be presenting the results of his practice’s two-year research project, the New Model Building, a standardised seven-storey building.
The open-source methodology - produced in collaboration with the likes of University College London, Timber Development UK, and Buro Happold - is available for all architects to use, but is not prescriptive except for the junction details. Instead, it outlines a set of principles and guidance for the design and construction of multi-storey, mass-timber buildings that architects can reference and adapt to their own projects.
Read more about the Mass Timber Insurance Playbook
Can the UK be a structural timber champion?
“Timber is still perceived as a risk by developers,” Anthony says. “They know the risks for steel and concrete costs and construction, but not for timber. We want to de-risk structural timber and remove questions about insurance, warranties and any regulatory sign-off. We’re saying it can be done.”
The UK could yet go from lagging behind when it comes to using structural timber, to a champion in this field.
'Navigating structural timber construction to address Net Zero' conference
Curated and staged by the Structural Timber Association and hosted by RIBA at 66 Portland Place, London, the conference features respected guests in this field – including Anthony and RIBA’s own Technical Advisor (Sustainability), Jess Hrivnak – speaking about structural timber, what progress has been made in this area, and other topics.
Book your ticket to the conference on 2 July 2024.
Thanks to Anthony Thistleton-Smith, Founder and Director, Waugh Thistleton
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RIBA Core curriculum topic: Sustainable architecture.
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