The state of Oregon recently became the first in the country to approve the use of science-based building code requirements for “tall mass timber buildings,” under its Statewide Alternate Method (SAM). The SAM approval lays a path for the state and perhaps the rest of the country to usher in an increase in the use of mass timber wood products in commercial and residential buildings. Prior to the ruling, structures of this type were limited to six stories in height.
The types of lumber affected by the code change include cross laminated timber, structural composite lumber, and mass timber which is defined as structural elements made primarily from solid, built-up, panelized or engineered wood products. The new regulations were cheered by the American Wood Council (AWC).
AWC President & CEO Robert Glowinski says, “Mass timber is a new category of wood products that will revolutionize how America builds and we’ve seen interest in it continue to grow over the last several years. This action by the Codes Division Administrator helps code officials in Oregon by making provisions consistent throughout the state. In adopting this new method, Oregon has also recognized the significant environmental benefits that accrue from greater wood product use.”
The Oregon ruling follows the work of the International Code Council, who has also been investigating how and if engineered wood products can be better incorporated into taller structures. The use of wood in tall buildings was sidelined by fire codes that date back to early 1900s. As firefighting techniques have improved and wood has become less prone to fire through engineering, architects and builders have been tinkering with the idea of adding more timber into taller buildings.
Cutting construction costs and reducing the carbon footprint of a project remain intriguing aspects to the increased use of wood products in tall buildings, experts say. The trend has already grown some international roots as Britain’s Waugh Thistleton Architects boasts the design and construction of Dalston Works, a 10-story multifamily building in London made entirely from cross laminated timber. According to the designers, the 121-unit building weighs one-fifth of weight of a comparable concrete building and was built with 80% less construction deliveries.