Why mass timber is becoming increasingly popular | foresight.skanska.com
DECARBONIZING CONSTRUCTION

Wonderful wood: the benefits of mass timber

If you think large structures like offices and apartment blocks have to be made from reinforced concrete, think again. Mass timber buildings, using structural elements made from engineered wood, are popping up across the planet on a range of different scales. They can deliver major benefits in both sustainability and user experience.

Go back a couple hundred years and wood was one of the most common construction materials used in the world’s cities. That changed in the 20th century when modern reinforced concrete became the building material of choice, particularly for larger projects. But now the pendulum is swinging back to wood, with structures including public buildings, offices and apartments being built using mass timber technology.     

 

In the latest episode of our Shaping Sustainable Places podcast, we talk with two experts with deep knowledge of mass timber construction. Andrew Waugh is a founding  director of Waugh Thistleton Architects, the company responsible for Murray Grove, the world’s first all-timber residential tower. Dean Lewis, meanwhile, is Director of Mass Timber and Prefabrication with Skanska in Seattle in the USA and has been involved in our landmark Portland Airport expansion project.

 

Glued or nailed

 

Andrew explains that mass timber products are created by gluing together wood under pressure or nailing together layers of wood to create structural panels, posts and beams.

He says as well as being strong, beautiful and easy to prefabricate, such elements store carbon, making them highly sustainable compared to steel and concrete.

 

Dean points out another sustainability benefit of mass timber structures comes when they are eventually demolished, as the timber components can be easily removed and repurposed.

 

Dean says Skanska USA has employed a mass timber approach on more than 20 projects since 2000. One example is the Portland International Airport expansion project where we helped erect a 37,000 square meter mass timber roof over the existing airport. Some 6,000 cubic meters (2.5 million board feet) of locally sourced timber was used, with the roof comprising 16 separate cassettes.

 

Significantly less carbon

 

Dean also highlights a recent study funded by the US Department of Agriculture which examined the carbon savings of using mass timber on a mixed use development in Wisconsin. When emissions related to material production and transport were considered, mass timber reduced embodied carbon by 20 percent compared to concrete and steel. But when the ‘biogenic’ carbon stored in the mass timber was also considered, the reduction was 60 percent.

 

Andrew says the mass timber construction movement is still in its infancy. While the world is building the equivalent of a new New York City every month, he says the number of mass timber buildings being constructed might only amount to a village every year.

 

Dean says for the technique to gain traction some myths need to be dispelled. One is that there aren’t enough trees for the widespread use of mass timber. However, with properly managed forests there is plenty of wood. Another is that mass timber is expensive. As Skanska projects have demonstrated, mass timber projects can be delivered for the same or lower cost as conventional projects.

 

You can tune in, listen and subscribe to the podcast on Spotify, Apple Podcasts or Google Podcasts.