The STA sat down to talk with Lee Roberts, Pre-Construction Director at B&K Structures about his experience with mass timber construction, potential barriers for the increased use of mass timber and his thoughts on the market outlook for the industry.

Tell us about B&K’s experience with mass timber, such as the type of systems specified and the key drivers for clients’ selecting the material.

B&K Structures have been delivering mass timber construction projects in the UK since around 2007. We have two core systems that we design and build – timber-steel hybrids and full mass timber solutions, using glulam and CLT panels. We operate in a diverse range of sectors, with commercial being our key sector, accounting for around 60% of our projects.

In terms of key drivers, it really depends on the client and their requirements. What is important for one client, may not be a priority for another. However, one common theme we have seen is that mass timber is specified more frequently due to its sustainability benefits, along with the speed of construction and offsite capabilities.

Is the volume of mass timber projects increasing and if so, at what pace? Are clients more interested in mass timber and what is driving this interest?

Yes, I would say that these types of projects are increasing, and the scale of these projects are substantially larger in recent years. In fact, the average project size is probably two to three times larger than it was 5 years ago. I think this is a direct result of the increased level of confidence in building with timber at scale, along with proven examples of timber being utilised for refurbishment projects, such as our Gramophone Works project which won Commercial Project of the Year in the 2022 Offsite Awards and Project of the Year at the 2022 Structural Timber Awards. The Gramophone Works is a refurbished factory in Kensington which consists of a timber frame around an existing two-storey reinforced concrete frame to fulfil the capacity of the space.

What are the biggest challenges in getting mass timber projects over the line – e.g. is it client demand, industry red tape, insurance problems etc? What can be done to overcome these hurdles?

A historical challenge for mass timber was insurance, however, even this has somewhat alleviated in recent years as more research and testing has been provided by organisations like the STA, which has generated much more confidence in insuring timber. Years ago, as specialist timber subcontractors we were rarely involved in early talks with brokers and insurers about insuring engineered timber structures yet to be constructed. There is still work to be done in the industry to ensure these systems are universally accepted and understood, but the progress is clear to see.

One thing that can really help get mass timber projects off the ground is considering efficient material choice at the design stage, and really early engagement between all parties, particularly specialist timber subcontractors, who have vast experience of overcoming the challenges associated with the design and delivery of engineered timber structures and can offer early advice. It is crucial from the outset of all projects, that a pragmatic approach is applied to selecting the right material, with the right principles for the building being designed.

There is so much to consider at the design stage from fire, durability, budget and of course, legislation. By having a design team and project team that understand timber and how to design with it, any risks can be mitigated and designed out at an early stage, increasing the speed and ease of construction, and producing buildings with peak performance across the board. We are really pushing clients that aspire to build with timber to engage with us pre-construction for advice and help, to mitigate those risks.

What do you think the structural timber industry should be doing to increase the use of mass timber? How can Government policy help with this?

Research and development are key for the mass timber industry. The more testing and data that is available, the more confidence insurers and investors will have in the material and the perception of timber will improve, especially when it comes to fire and durability.

The Government has a role to play in this. Something that we hope to see from policymakers is much clearer communication about what they need to see in order to back timber as the best construction method to achieve net zero targets. We would also like to know exactly what they want to see in order to overcome the red tape in place for things like Part B.

Where do you see the future of mass timber going?

I see the market continuing its growth in the next decade, just as it has grown over the last decade or so. As clients become more aware and comfortable with the products, I foresee a rise in clients specifying mass timber, particularly in refurbishment schemes where timber can be utilised to refurbish and repurpose buildings which might otherwise be knocked down. This is where hybrid construction can really provide value, adding timber elements to existing frames and structures. Hybrid construction offers an effective way to integrate more sustainable materials into projects while also satisfying questions insurers may have about building with timber.

People are beginning to get creative with timber for buildings like warehouses and office blocks – I think there are a lot of opportunities for these projects and it is an exciting period for sure. Luckily, we now have a lot of information and data at our disposal such as the recently published Structural timber buildings fire safety in use guidance Volume 6 – Mass timber structures; Building Regulation compliance B3(1) produced by the STA, and with all of this industry guidance available, the growth is inevitable.

We are also expecting to see a lot more growth geographically. London is the predominant location for timber and hybrid buildings, but this is slowly moving into areas like Birmingham, Manchester and Leeds, so we’re certainly hoping to see more of these types of buildings around the country.

B&K Structures are the UK’s leading sustainable structural frame contractor, specialising in the design and delivery of hybrid structures. They have been in operation since 1974 and have worked with some of the UK’s biggest clients to build projects with outstanding green credentials. Learn more about B&K Structures here: https://www.bkstructures.co.uk/

---