Carbon12

At the time Carbon12 was completed in 2017, this eight-story structure was the tallest mass timber building in the U.S. Comprised of a glulam post-and-beam frame and cross-laminated timber (CLT) floors and ceilings, the 85-foot building sets a precedent for taller wood projects in the Pacific Northwest. The decision to use mass timber instead of concrete was driven by the developer’s desire to build an environmentally sustainable multi-family project utilizing regionally-available and renewable timber resources. To provide seismic and lateral support, designers combined glulam beams and CLT floor decks with an innovative buckling-restrained steel brace-frame core. The building’s thick basement slab rests on 41 steel pilings driven 45 feet deep, providing additional lateral stability. Mass timber’s ability to char delivers natural fire protection, which allowed designers to leave the wood exposed throughout the building’s interior. Carbon12 houses 14 residential units with a ground-floor lobby and retail space.