The use of mass timber in the commercial sector has seen a recent flourishing in the UK, with increasing interest from investors. Here, some of the frontrunners in the industry explain why.
Occupiers want healthy and sustainable workspaces
Alex Dunn, research manager at Cromwell Property Group, has undertaken extensive research into the modern office, tracking recent shifts in working practices and the changing priorities of occupiers. He explains that there is a real demand from occupiers to lease spaces that align with their sustainability goals and show that they value their employees’ wellbeing.
With studies demonstrating that biophilic design can improve employee health and wellbeing by 13% and productivity by 8% , and that timber surfaces provide stress-reducing effects , Dunn notes that it is no wonder occupiers are seeking greener offices from investors and landlords.
Energy and carbon saving
An ever-widening awareness of the urgency in reducing both operational and embodied energy has led many clients, designers and developers to converge around timber building.
Mass timber has a higher thermal resistivity than concrete, masonry or steel, which helps to regulate temperatures and improve operational energy efficiency.
But, as well as demanding low operational energy, occupiers are also becoming increasingly aware of the embodied carbon in their buildings – and this is one of the key factors making timber more attractive to investors.
By minimizing the use of carbon-heavy building materials such as steel and concrete, and locking carbon into the material, the use of mass timber can dramatically reduce the embodied carbon of a development.
The potential of mass timber in creating low-carbon office spaces has been exemplified in the recently completed Black & White Building in Shoreditch – currently the tallest timber office building in London. For this building, comparative carbon calculations by architects Waugh Thistleton showed that there was a 63% reduction in carbon than if it had been built from concrete – with this saving rising to 73% when the sequestered carbon is considered.
When the Black & White Building opened, BVN Architecture decided to make it their London studio’s home. As an international practice committed to creating inclusive and sustainable places for people to work, BVN required a location that met their sustainability ambitions and was aligned to their ethos and philosophies. Principal Matthew Blair explains that the move “allowed us to live what we say.”
Bouncing ideas between Brisbane, Sydney, New York and London, BVN have been ambitiously evolving the way they design workplaces, combining the comfort of contemporary commercial buildings with the benefits of timber and the biophilic benefits of connection to the outside.
Explaining why so many of their projects use timber construction, Blair says “as well as the structural, construction, and sustainable benefits of timber, one of the reasons we consider it on every project we use, is because it makes wonderful environments for people: timber brings the delight without having to work too hard.”
Retention and reuse with timber on top
Another way that mass timber is supporting the development of unique, low carbon commercial projects is its application in the reuse and extension of existing buildings. Often requiring no, or minimal, reinforcing of foundations, vertical timber extensions can maximise the use of existing resources while significantly adding to the floor area.
“Vertical extensions to existing buildings are one of timber’s sweet spots,” declares Peter Fisher of Bennetts Associates – the architectural practice behind the currently onsite Timber Square.
Consisting of two separate office buildings, the project is partly a reuse of a 1950s printworks, which will be extended vertically with CLT, and an adjacent steel-timber hybrid new-build. Fisher explains that the use of CLT, which is about 25% lighter than using steel, has enabled the creation of an additional storey on top of the building.
Scheduled to be completed in 2025, this highly bespoke project has required a lot of testing, and the designers have found many advantages to using CLT, contributing to its longevity, carbon impact and character.
“In the next two or three years I think we will see many more of these kinds of schemes coming through.”
Safety and speed in construction
Real estate group Lendlease have been advancing the use of mass timber internationally for over a decade. Technical leader Mario Lara Ledermann explains that, as well as helping them to achieve their ambitious carbon reduction targets for net zero by 2030 and absolute zero by 2040, they are seeing a host of further advantages to mass timber because of modern methods of construction.
“As well as reducing carbon emissions, there are real benefits to mass timber from a safety in construction perspective and a processing and programme standpoint.”
Ledermann describes how reduced risks onsite – including the removal of the need for scaffolding and the reduction of dust and pollution – are enabled by prefabrication and ‘kit of parts’ approaches, making for safer, quieter and more pleasant working conditions.
Quicker speed of construction plus the requirement for fewer lorry loads and less cranage – because of timber’s lesser weight – mean that there are often savings in both time and cost to mass timber construction.
In research conducted by Stora Enso, the development costs of three hypothetical office buildings were compared in timber, steel and concrete. Across the examples, timber was shown to be on average 3% more expensive than concrete and 1% cheaper than steel.
However, the range of financial benefits of timber, such as lower labour requirements and quicker construction schedules, make it a cost-competitive construction material.
This builds on the already compelling case to using mass timber in terms of carbon, occupant wellbeing and onsite safety, offering important assurance to investors that it is also financially viable.
Standing out in a crowded market
Given that the availability of mass timber offices in the UK is currently low, those that exist also have a competitive advantage in attracting occupiers. In rent comparison research conducted by Cromwell, they found a 9% rental premium on recently let timber buildings in Europe.
“Occupiers and investors are targeting greener real estate and we strongly believe timber is a good solution for this. Environmentally, it’s a very strong case, but when you factor in things like rental premiums, financially it makes sense as well. As more timber buildings pop up out of the ground, it will give investors confidence that this is a tangible solution, and we will hopefully see it snowball over the next decade.”
Alex Dunn, Cromwell Property Group.
 Pollinate Health Report, 2018
 Fell, D. R. Wood in the Human Environment: Restorative Properties of Wood in the Built Indoor Environment. PhD Thesis, University of British Columbia, 2010.
Featured image: The Black and White Building by Waugh Thistleton. Image © The Office Group. Photography by Ed Reeve.