Filling the knowledge gap and helping developers create sustainable timber buildings

As the one of the UK’s premier fire engineering experts, our founder Sam Liptrott was this week called to the House of Commons Environmental Audit Committee to give written and verbal evidence as part of the sustainability of the built environment enquiry — you can watch his appearance here.

Now, Sam explains the role of timber in a sustainable future for construction — and how investing in the knowledge gap can help timber be more widely — and safely — used across the country.

We need more homes and we need homes to be created in a sustainable way, using materials that will safely stand the test of time.

For many, timber is the obvious solution to this, but in recent years it’s a material that’s come under much scrutiny (albeit for very valid reasons). So many questions — not least what is tantamount to a ban from central government and local authorities on its use in residential development — have led the insurance sector to largely withdraw their willingness to cover it.

It was a hot topic in the Commons this week, and I was honoured to offer evidence in to discuss the industry’s position. I’m hugely passionate about change through education and described myself not as someone pro-timber, but pro-science — conveying my hopes for addressing the knowledge and competence gap in this country with robust research and evidence that promotes confidence.

Right now, we are in a difficult position in the UK. Construction is negatively contributing to the climate crisis, accounting for 40% of all global carbon emissions — with UK builders responsible for 25% of the total UK carbon footprint.

Current restrictions on the use of timber takes away most hope of redressing this balance, with developers often swapping out timber for concrete and steel. These materials perform nowhere near as efficiently as timber, but their perceived reliability means they are widely accepted by approvers and insurers.

But there are downsides; on account of their weight, steel and concrete buildings can’t be built at the same scale as timber developments — something that leads to smaller schemes and less homes. Add to this a planning system that is in a Catch-22 and can’t incentivise mass timber use without guidance; and of course, a vacuum of confidence from approvers and insurers — you can soon see the issue.

There are however developers trying to lead on change. At the vanguard of the construction industry, there are extremely competent and visionary developers, designers and contractors who want to achieve net-zero in a safe and sustainable way. This is already being seen on numerous projects, buildings, and pan-industry initiatives.

Their determination, exemplary developments and investment in research can pave the way for timber. Let’s not forget, this is a great, regenerative material that will help the construction sector, not to mention offsite and modern methods of construction which by their very virtue will help reduce the sector’s carbon footprint — creating buildings offsite for example in precision manufactured environments equals less waste and less site traffic — fundamental changes which en-masse would decrease the sector’s carbon impact.

In addressing the relative paucity of competence when it comes to designing and building with timber we can establish more confidence. We can’t lead by example when we are in a country in which there aren’t many timber buildings to begin with (not when compared to European examples). That means less trust, and less buy-in from insurers, local authorities and, of course, end-users.

As I advocated in the Commons, the most meaningful incentive would be a significant investment in experiments and the development of knowledge to be able to create guidance and a framework for timber to be used safely. If we can substantiate research with scientific support, then we can counter the current arguments.

If we can generate enough knowledge to establish guidance then we can set out a path to meeting the Building Regulations and concerns of the Statutory Approvers (Building Control Bodies) and Fire Services, there would be significantly move interest from developers to use timber. However, as my colleague discusses in a recent Architects Journal article, ( the construction industry needs to stop perpetuating pseudo-science when it comes to the fire hazards associated with mass timber construction. Acknowledging the existence of these hazards is a prerequisite for generating the knowledge to develop solutions and robust designs. Statements from articles by fire engineers and architects (see references below) are misleading and serve to give the impression that sufficient knowledge exists to build without concerns or constraints, for example:

“..wood is one of the most predictable elements in terms of fire, scientists tend to know almost exactly how it reacts, and the amount of charring it undergoes.”


“It’s fire-safe, too. CLT is very slow to ignite, designed here with an additional 4cm sacrificial layer on each side that would char in the event of a fire, protecting the structure for 120 minutes.”

Recent articles by Collaborative Reporting for Safer Structures UK (CROSS-UK)( have tried to debunk such statements and myths, highlighting that the use of mass timber is not a common building situation and, as such, more considered design approaches are often required. This is progress in the right direction. It may feel to some supporters of timber that acceptance has moved backwards, but the false claims of timber being inherently “fire-safe” and “predictable” need to be laid to rest and replaced with a more nuanced and science led narrative to assure adequate safety is delivered.

There’s a precedent for this investment in generating fire safety knowledge; we only have to look at the money and time invested in the steel industry in researching how the material could be used and subsequently how it could be optimised through the large-scale experiments undertaken at Cardington in the 1990s. We maybe don’t need to go to that extent with timber, but it needn’t be something that the industry do alone; it’s encouraging to see developers and others in the sector investing in the early stages of research but right now it’s not matched by the Government.

This could change. It would be welcomed if the Government engaged, and if insurers and other approvers came on the knowledge journey; together we can establish scientific principles and a framework which allows for a safe and sustainable built environment.


Timber & Sustainability

Sam Liptrott


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