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A 12-story mass timber tower in downtown Portland has become Oregon鈥檚 tallest mass timber residential building, delivering 90 units of permanent supportive housing for low-income seniors on one of the city鈥檚 most constrained urban infill sites.
Julia West House, at 522 S.W. 13th Ave., rises 145 feet on a 6,000-square-foot lot 鈥� roughly one-eighth of a city block 鈥� and provides fully furnished apartments for individuals earning 30 percent or less of area median income. Community Development Partners developed the project, with Holst Architecture serving as architect, Walsh Construction as general contractor, and KPFF as structural engineer. Carpentry Plus handled mass timber installation.
The building鈥檚 Type IV-B mass timber structural system features five-ply cross-laminated timber floor panels supported by a glulam post-and-beam frame with a steel braced lateral system. The team estimated the mass timber approach delivered approximately 13 weeks of schedule savings compared to conventional concrete construction, helping offset material cost premiums.
Among the project鈥檚 technical innovations, engineers developed two-way spanning CLT corridor panels that eliminated downturned beams, allowing mechanical systems to route more efficiently while maintaining ceiling height. The building was engineered almost entirely with bolted connections, eliminating on-site welding to reduce fire risk, airborne hazards, and fall exposure. Floor assemblies achieved STC 56 and IIC 53 acoustic ratings, surpassing many market-rate multifamily standards. Fire resistance for exposed timber was achieved through char calculations, gypsum encapsulation, and project-specific fire engineering that required formal code appeals.
Weekly floor installation sequencing 鈥� one mass timber level per week 鈥� created a controlled vertical construction environment, limiting prolonged exposure to work at height and enabling predictable trade coordination on the tight urban site.
The building targets National Green Building Standard and Energy Star certification, incorporates all-electric systems, and received $2 million from the Portland Clean Energy Community Benefits Fund. Financing included 4 percent Low-Income Housing Tax Credits and USDA Wood Innovations funding.
Approximately 34 percent of total project cost was delivered through minority-, women-, and emerging-owned businesses.
Nearly a quarter of Portland鈥檚 houseless population is 55 or older, with BIPOC elders disproportionately represented. Approximately 45 percent of Julia West House residents identify as BIPOC. Culturally specific services are provided for 20 Native households through the Native American Rehabilitation Association of the Northwest.
鈥淭his was a really exciting project to use a brand-new-to-us construction typology in mass timber, and a high-rise,鈥� said Eric Paine, CEO of Community Development Partners, in the project nomination form. 鈥淚t was the first time we had used cross-laminated timber in a multi-story building, and it was the tallest building that CDP has ever developed.鈥�