MASS TIMBER By Judith Sheine, AIA

One of the new mass timber products is Cross Laminated Timber (CLT). CLT was first explored in Switzerland and then developed in Austria in the mid 1990s; it has since become increasingly popular in Europe, particularly over the last 10 years. CLT panels are made up of layers of 2’ x 6” dimensional lumber glued perpendicular to each other. They are typically 10’ wide, up to 60’ long, and range from 4 ½” (three layers) to 10 ½” (seven layers). CLT can replace concrete in buildings in floors and walls. Because the panels sequester carbon they are

photos by erik bishoff, steve smith, len stolfo and chambers construction

There is much excitement in Oregon these days about the potential of new mass timber products to revitalize the timber economy in rural communities, as well as to create sustainable, healthy buildings. Timber has historically been of critical importance to the economic base of Oregon, with the logging and timber production industries central to the development of the state. However, since the 1970s, with the impact of the 1973 Endangered Species Act on the reduction of logging, and the increasing automation of the industry, jobs in the timber sector have been shrinking significantly. Recently, for the first time in many years, environmentalists and the timber industries have come together to support the production of new engineered timber products that use small pieces of wood glued together to make large strong

panels for use in construction. Instead of using old growth trees, the new products are made of small logs that can be sustainably grown and harvested and also make use of smaller trees that can be culled from forests to promote their healthy growth and help to prevent the massive forest fires we have seen recently in the west.

AMERICAN INSTITUTE OF ARCHITECTS | SOUTHWESTERN OREGON CHAPTER

DR Johnson CLT panel being set into the roof deck for Albina Yard, Portland, OR, Lever Architecture

inherently more sustainable than concrete and steel products, which employ manufacturing processes with significant carbon footprints. CLT, like other engineered timber products such as glued laminated beams and columns, has other advantages over concrete and steel. It is much lighter, reducing the weight and foundations required in buildings, and it can take advan-

tage of new digital fabrication tools that can make openings for doors and windows and cuts for connections. The panels are made “on demand,” as custom orders, using digital files, loaded onto a truck, driven to a construction site, and quickly and quietly assembled, saving labor and time over (Continued on pg. 12)

“Building What’s Important instreaks People’s Lives” Traffic on Franklin Boulevard by the University of Oregon’s Matthew Knight Arena in Eugene. Traffic on Franklin Boulevard streaks by the University of

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