Carbon12

Carbon12 is an eight-story, 95-foot-tall mixed-use CLT condominium in Portland, Oregon. Upon completion, it was the tallest CLT building in the United States and helped establish new code precedents for tall wood construction nationwide.

The loft-like floor plan ensures that each unit has direct access from both the elevator and stairs, enhancing accessibility and convenience. The modern layout removes barriers for easier entry, blending luxury with thoughtful design.

By choosing mass timber, we avoided 221 metric tons of carbon dioxide emissions. Additionally, because wood weighs only approximately 20% as much as reinforced concrete, we significantly reduced the demands on the foundation and lateral system.

When Carbon12 was designed, U.S. and Oregon building codes restricted wood structures to 65 feet (five stories). The Oregon Building Codes Division reviewed early CLT projects, using Carbon12 as a model to establish processes for local jurisdictions. This work ultimately influenced national code updates, contributing to the new Type IV-C building classification in the 2021 IBC.

Our unique team structure, acting as developer, architect, and contractor, enabled early collaboration with subcontractors and the mass timber supplier. By coordinating MEP, sequencing, and the steel-to-wood interface from the start, we streamlined construction. As a result, the structure was completed in just eight weeks, compared to the twenty weeks typically required for concrete.

Key Facts

Height: 95’, 8 Stories

Area: 40,000sf

Program: 2 Retail + 14 Residential - Condominium

Building Type: Type III-A with Height Exception (model for future Type IV-C)

Structural System: Mass Timber Columns, Beams, and Floors, BRB Core

Location: Portland, OR, USA

Architect and Developer: Kaiser + Path