Bevel Tower: North America’s Tallest Mass Timber Office Building

A proposed tower in Bellevue, Washington, set to become the tallest mass timber office building in North America, aims to achieve a new architectural milestone. The design by Mithun and Waugh Thistleton Architects (WTA) makes timber the core material for construction.

Bevel, a 12-story, 55-meter (180 feet) tall structure, is led by development firm Skanska, known for projects like MetLife Stadium in New Jersey and 30 St Mary Axe in London. Skanska emphasized that Bevel’s success lies in prioritizing timber as the primary design element rather than treating it as another building material.

Bevel could demonstrate mass timber’s commercial viability at scale. Yet, interpreting building codes for this unprecedented project poses a challenge, Skanska explained. Timber housing projects have used Type IVB construction provisions, allowing mass timber or non-combustible materials with fire-resistance ratings. No commercial office building has been constructed under these specific codes before.

The unveiling follows another timber milestone. Atlassian Central in Sydney, Australia, reached a height of over 180 meters (around 590 feet) in July, marking the world’s tallest hybrid timber tower.

Bevel’s Design Innovations

Jennifer Cover, CEO of WoodWorks, highlights Bevel’s role as the tallest upcoming mass timber office building in the U.S. Of 22 tall timber buildings recently constructed or under development, only three are commercial. Bevel’s fully exposed timber ceilings offer new design possibilities to other architects.

Originally conceived as both a concrete and mass timber building, a cost comparison revealed parity. Designing specifically for timber avoided retrofitting challenges. Mass timber columns, beams, and ceilings will feature prominently, supported by steel for seismic stability, and concrete parking levels below ground.

Sustainability and Biophilic Design

Targeting LEED v4 Platinum certification, Bevel incorporates advanced sustainability features. Stormwater reuse systems, energy-efficient systems with full electrification, and biodiversity-focused design stand out.

Biophilic design integrates nature-infused elements. The lobby will feature floor-to-ceiling glazing and abundant natural light, promoting a soothing environment. If constructed, Bevel promises an innovative workplace that emphasizes connection, wellness, and a strong sense of place.