7 minute read
Mass Timber Office Forum
Oliver Hartley-Booth outlines the topics discussed by this focus group to help increase the use of mass timber in the commercial office market.
In January 2020, as a member of the TRADA Advisory Committee, I was approached by several industry leading developers with an idea to set up a forum focusing on mass timber and hybrid construction, specifically relating to the commercial office market.
Popularity and uptake of mass timber and hybrid structures has been rapidly increasing in the past five years for many reasons. More recently the urgency to address the climate change crisis and increased focus on improving the health and well-being of the end-user has propelled this form of office construction to the forefront of commercial developments across the UK. The embodied carbon credentials of timber have an incredibly important role in reaching the ambitious targets that the UK and many countries around the world have set to achieve net zero carbon by 2050 or before, to begin to tackle the effects of climate change.
Structure and aims
The team at Gardiner & Theobald (G&T) set about structuring the forum’s sessions into the following categories:
The main purpose of the Mass Timber Office Forum is to bring together experts and stakeholders from across the industry to discuss and debate the barriers to using mass timber in office construction.
Originally due to be held in person at G&T’s headquarters, the series had to pivot and reorganise digitally due to the impact of Covid-19 and the national lockdown implemented in March 2020. However, this challenge presented a fantastic opportunity to host these sessions as webinars that could be recorded and then distributed to a larger audience to share knowledge and experiences.
TRADA, the Timber Trade Federation and the Structural Timber Association are part of the forum audience, and are actively collaborating to ensure the lessons from these sessions are disseminated across the wider industry.
The forum is co-hosted by G&T’s Matt Holman (the Chair) and myself, and the monthly sessions focus on hot topics to help share knowledge and information that can be referred to when considering mass timber for commercial office projects.
To date, eight successful webinars have taken place, discussing key topics such as insurance, fire, sustainability, capacity, best practice in construction and cost.
The insurance forum
Voted by the audience to be the number one barrier to market for mass timber office buildings, the first session discussed:
• the value of the mass timber industry1 • current barriers to market • the way forward with the insurance of mass timber offices both during and post-construction.
The use of mass timber across the industry is increasing, generating a wider debate in the insurance industry on the assessment of timber buildings to evaluate the insurance premium requirements against the differing risks to concrete and steel structure frames. Some of these risks don’t fit easily into long-established construction classes and comparatively little statistical data exists to help insurers when underwriting mass timber buildings.
Experts included: Andy Desmond of Marsh, Dominic Lion of Gallaghers, Caroline Hairsine and Oliver Wright from Aviva, Andy Penny and Robert Innes of Zurich, Nick Tilley from AXA, and David Lyle from Lockton.
The panel discussed how these challenges also present opportunities for the sector, and how increased collaboration across the supply chain, data sharing and early initial engagement with the insurance industry could help mitigate these risks. >>
Figure 1: Elements of design affected by the use of mass timber in offices. Source: Gardiner & Theobald LLP
The fire, testing and building control forum
The second session discussed the issue of fire in mass timber2 in both pre- and post-construction, as well as the work currently being done by stakeholders on the behaviour of mass timber buildings in the event of fire.
The panel of experts included: Sam Liptrott, Director at OFR Consultants; Judith Schulz, Director at Arup; Mark Pundsack, Assistant District Surveyor for City of London and Building Control; and Prof Jose Torero, Professor of Civil Engineering and Head of the Department of Civil, Environmental and Geomatic Engineering at University College London.
The group spoke about the importance of design when using mass timber products and how a few small changes could help to mitigate the risk of fire during construction. The forum audience were asked which elements of the design would be affected by the inclusion of mass timber and, as shown in Figure 1, although many answers were given the overriding message from the panel was that all elements of a development can be affected by the inclusion of mass timber making the design phase of a mass timber development extremely important.
The panel also responded to questions raised during the previous forum on insurance and how the industry can work together, sharing knowledge to mitigate risk and reduce insurance premiums for mass timber developments. The group agreed that there is much that can be learned from other countries; examples from the Netherlands and the US provide inspiration on how to incorporate greater use of mass timber within our developments. There was also an appreciation from the panel of differing approaches to risk and suggestions for how we could take the principles and processes adopted by these regions and apply them to our own UK standards and guidance.
The sustainability forum
The third session discussed the role that mass timber commercial office buildings can and will play in contributing towards the global net zero and sustainability agenda,3 as well as improving the health and well-being of a building’s occupants.
The panellists, including Simon Sturgis, Managing Partner at Targeting Zero, Anna Denell, Sustainability Director at Vasakronan and G&T’s Environment and Sustainability Director, Richard Francis, also discussed the potential impact mass timber can have on achieving net zero by 2050, with the audience being asked whether they thought the health benefits of mass timber will accelerate the transition to net zero – the overall majority voted ‘Yes’ (85%).
Best practice in construction
The fourth in the series, this panel discussion focused on best practice advice when using mass timber during >>
construction4 and had senior representatives from some of the most reputable main contractors across the country, all of whom had experience working on mass timber projects. Representatives from GRAHAM, Kier, Lendlease, Mace and Mid Group shared their experiences and lessons learned from using mass timber on recent projects.
The group all felt positive about working with mass timber and cited that preventing and dealing with water ingress is one of the key challenges, albeit they all agreed this risk can be mitigated in a variety of ways at the procurement stage. They also agreed that collaboration was important, not just within the UK but also when learning from international projects.
The cost and programme forum
In the fifth session the panel of experts focused on what implications using mass timber for office construction may have on a project’s cost, programme and the procurement approach,5 from the design phase right through to construction.
Comprising five G&T experts, Matt Holman, Steve Bennett, Paul Robinson, Jess Pennell and myself, the panel discussed the various steps and considerations that need to be made when choosing mass timber solutions.
Not only did the group consider pre-construction and the design phase of a project, but also the team that would need to be selected to deliver a mass timber project successfully and the stakeholders that would need to be consulted throughout the duration of a project. Collaboration was highlighted to be vital for the success of a mass timber project and, following a live poll (as shown in Figure 2 ), the audience voted 95% in favour of collaborating with other firms and key stakeholders to create a bespoke testing programme for these materials.
Remaining sessions
The series has examined the impact that using mass timber may have on the cost and programme of a project, as well as the capacity of the supply chain for mass timber and the considerations needed for the structure, MEP and acoustics.
The programme will conclude with a final session on architecture and design in April and culminate in a White Paper documenting the key considerations and learnings from each discussion, due for release in spring 2021. n
About the author
Oliver Hartley-Booth Partner Gardiner & Theobald
Further reading
• Cross-laminated timber: Design and performance, Revised reprint, ISBN 978-1-909594-63-0, BM TRADA, 2019 • Procuring engineered timber buildings: a client’s guide, ISBN 978-1-909594-78-4, BM TRADA, 2019
