Greater use of timber calls for pragmatism to keep insurers happy


The construction and insurance industries must work together if we are to increase the use of structural timber that is safe and cost effective, says Andrew Carpenter.

Increasing the use of structural timber is vital in the quest to meet construction’s net zero obligations, but the industry should adopt a pragmatic approach towards hybrid construction in order to overcome insurance hurdles.

This is broadly the line taken by the recent RISCAuthority report entitled Insurance Challenges of Mass Timber Construction and a Possible Way Forward. Investigating the risk of mass timber structures on behalf of 24 insurers, including Axa, Aviva and Zurich, the report concludes that adopting a hybrid approach is the best solution if we are to allay insurers’ concerns around fire and water damage.

Recommending that multi-storey mass timber buildings are constructed using a concrete core and lower levels, the report argues that this would make it much easier for insurers to offer their backing. At the Structural Timber Association (STA), we have always advocated using the right product for the right application and so we welcome this sensible approach, which could prove an easy route to increasing the overall volume of timber used in construction – thus delivering lower embodied carbon as a whole.

“Optimum product specification should be about choosing the right combination of products and materials for the individual application and client requirements”

Building materials such as timber, concrete, steel and glass each have their own particular profile of attributes and benefits. Logically, then, optimum product specification should be about choosing the right combination of products and materials for the individual application and client requirements – whether the priority is cost, carbon, speed of construction or aesthetics.

Not surprisingly, the STA believes that timber is an excellent building material when used in an appropriate context and our objective is to champion its many benefits. However, we firmly believe that this should be achieved by providing fact-based, unbiased information that facilitates informed specification choices.

The STA has always promoted timber based on scientific evidence that supports its use through fire-tested resilient solutions and guidance on mitigating the risk of water damage through correct design and installation practices.

To provide demonstrable evidence of timber’s fire performance, the STA has invested heavily in research, commissioning more than a third of a million pounds of fire resilience testing for lightweight structural timber systems. The results of this testing can be found in the STA Fire Research Pattern Book Volume 1, which can be downloaded from the STA website.

Additionally, a further £500,000 of fire testing is currently underway, funded collectively by all the main mass timber suppliers and manufacturers within the STA. Due to be completed later this year, the full details of the mass timber testing so far have been published on the STA website by the CLT special interest group.

In regard to tackling water damage, the STA has established a durability working group, which is tasked with addressing the risks around moisture ingress. The work is focused on bringing potential risks to the market’s attention and, by doing so, highlighting how appropriate design can be used to mitigate such risk.

The working group is developing a guide that will set out best practice to avoid any potential issues – in a similar vein to the already published document 16 Steps to Fire Safety, part of the Site Safe policy, which promotes good fire safety practice on construction sites and is mandatory for STA building system supply members.

“With the increased use of timber now enshrined in government policy, the construction and insurance industries must find ways of working together to make this a reality”

The guide will also recognise that not all durability risks can be fully mitigated during the design and build process, which is where the use of suitable monitoring technology can be deployed. The working group is set to review these options and is in dialogue with the Canadian Wood Council, which now has several buildings that are being monitored in this way.

Ultimately, with the increased use of timber now enshrined in government policy following the release of the Build Back Greener net zero strategy, the construction and insurance industries must find ways of working together to make this a reality.

We welcome discussions with the wider industry and, as such, we are pleased to be part of the cross-government and industry working group, which is tasked with safely increasing the use of timber.

Education is the key and we are actively engaging with the insurance industry via the Time for Timber campaign to communicate the wealth of testing evidence available and help them to understand the use of timber from a risk management perspective. To that end, we have produced a series of guides and a white paper, the Insurance Industry Guide to Mass Timber in the UK.

Furthermore, the insurance industry must also be confident that the performance of the material is matched by the competency of those installing it. This is where the role of quality and compliance schemes, such as STA Assure, is key.

Independent acknowledgement of such schemes is also critical and, as such, STA Assure is recognised by seven of the UK’s main building warranty providers.

Consisting of an audit, a Timber Frame Competency Award Scheme and the Site Safe fire risk under construction mitigation process, the route to achieving STA Assure compliance is suitably rigorous to provide reassurances for partners within the construction and insurance sectors.

Moving forwards, we would welcome further collaboration with stakeholders in these industries to achieve the overall goal of safely delivering lower carbon buildings.

Andrew Carpenter is chief executive of the Structural Timber Association

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