Why use CLT: talking with expert David Moses

FPInnovations recently launched the 2019 edition of the Canadian CLT Handbook, a completely revised version aimed at reflecting changes made in Canadian codes and standards since the 2011 edition, and helping support a larger use of cross-laminated timber (CLT).

Beyond science, FPInnovations wanted to share the opinion of engineer David Moses*, from structural engineer firm Moses Structural Engineers, who has many CLT projects to his credit. Here’s what he had to say.

FPI: What was your motivation to use wood, and particularly CLT, in the first place?

DM: I was introduced to woodworking by a very dedicated teacher in high school – he emphasized the craft, understanding the material qualities of wood and working with traditional hand tools from around the world. The grain, the feel and the adaptability appealed to me. I did not realize you could design large structures in wood until I completed my degree in engineering. At that same time, the technology was changing quickly for connections, fabrication and modelling. CLT was a great next step for a new product that was very strong, could be precision-cut and could be installed rapidly.

FPI: How did people perceive this change? How do clients/occupants react to the use of wood in their environment?

DM: At first, designing and building with wood was a niche. Finding the right clients who shared our passion for these structures was not easy. And it varied geographically. But now, attitudes are changing, and more people are coming to understand the value of using wood in their buildings, be it for aesthetics, biophilic response or the environment.

FPI: What were the main obstacles you encountered from your clients when proposing wood in your projects?

DM: Like any structural product, we normally get questions about supply chain, scheduling, cost and performance. New construction products such as CLT take time to penetrate the market. I have seen this repeatedly over my career – it seems to take about ten years for the market to accept new products – a lot of people want to be the second or third to try something new.

FPI: The 2019 edition of the Handbook includes a new chapter, “Design Example,” of which you are a lead author. How did you come up to be associated with this project? What is the added value of this chapter?

DM: I was fortunate to be involved in the first CLT building in Canada and that was prior to there being any standards or building code approvals. We had to do our homework and study all the research literature available to us from other countries. From that experience, I went on to work with FPInnovations and the Canadian Wood Council to develop a short course on CLT design which we presented in major cities across Canada. Once the first edition of the Handbook was published, it gave practitioners an opportunity to dive deep into their understanding of CLT design. The natural next step was to provide a worked example for practitioners of a tall wood building to make it more accessible to more designers.

FPI: Why should professionals get their copy of the Handbook and use it in their projects?

DM: The Handbook has every topic covered and is an essential resource for anyone thinking of building with CLT for their first time. They will definitely refer back to it for the second, third or fourth buildings, whether they are in North America or other parts of the world.

FPI: Over the past years, many major construction projects using wood have been built in Canada. Do you believe this trend will continue? How can the Handbook make a difference in that regard?

DM: There is much more interest in wood for large-scale projects than in the past. This interest will continue as the supply chain increases product availability and as governments look for opportunities to incentivise atmospheric carbon reductions and promote their local forestry industries. The Handbook is the primary resource for designers and allows them to answer many of the questions asked by building owners. With more knowledge, we expect less perceived risk and more market acceptance.

* David Moses is one of Canada’s foremost experts on timber structures, heavy timber, glulam and CLT, and an advocate for advances in structural engineering and industry standards. His extensive portfolio includes the first Canadian CLT and passive house buildings and the Art Gallery of Ontario renovation. He is one of the lead authors of the Canadian CLT Handbook’s Chapter 13, “Design Example.”

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