Why CLT?

Designers choose wood for a variety of reasons—including aesthetics, cost effectiveness and environmental performance—many of which are the same for CLT. However, CLT also builds on these advantages with several of its own. This section provides a high-level overview of these benefits, and is followed by a closer look at issues of particular importance to structural engineers.

Speed and efficiency of installation. CLT panels are manufactured for specific applications. They are prefabricated, complete with pre-cut openings for doors, windows, stairs, service channels and ducts, and shipped directly from the manufacturer to the job site, where they can be quickly and efficiently lifted into place. This can shave months off the construction schedule. Many manufacturers ship panels with pre-installed lifting straps; contractors then use cranes to lift panels into place. Because panels are designed for specific end-use applications, they are often delivered and erected using a “just-in-time” construction method, making CLT ideal for projects with limited on-site storage capacity.

When Bridport House (see image) in London was constructed in 2011, it was the largest contemporary timber-built apartment block in the world. The CLT construction was completed in 12 weeks, by four skilled laborers and one supervisor.³

CLT’s relative light weight made it ideal for the five- and eight-story Bridport House, located over a large storm sewer in London’s Hackney Borough. Photo courtesy of Karakusevic Carson Architects

Design flexibility. CLT can be used for an entire building or any combination of wall, floor/ceiling and roof applications. Its light weight and other characteristics make it highly adaptable to different types of projects, designs and site conditions like soft soils or tight proximity to neighboring buildings. CLT elements can also be combined with other building materials, enabling flexibility in design, style and finish architecture. When field modifications are needed, one of the advantages of CLT over materials such as precast concrete is that changes can be made on site with simple tools, pending approval by the engineer of record.