While many cross-laminated timber (CLT) buildings have tested the vertical limits of the product, San Francisco–based architecture firm WRNS Studio recently set a record by designing North America’s largest CLT building in floor area. At over 644,000 square feet, the firm’s addition to Microsoft Silicon Valley, part of a larger renovation of the Moutain View campus, demonstrates CLT’s potential as a building material for expansive horizontal structures.
Given how few CLT projects currently exist in Northern California, the mixed-use building’s construction required thorough coordination between the project team and the local building authority to determine the optimal methods for engineering with the product. Extensive research was required to ensure that the swaths of exposed CLT would achieve fire ratings suitable for a building of its size in blaze-prone California. Local engineering firm Holmes Structures developed lightweight CLT floor plates that conceal the building’s immense power and data infrastructure beneath a thin top layer of cement. These CLT-concrete composite slabs require few load-bearing beams and columns, allowing copious amounts of sunlight to illuminate the building’s expansive interiors.
In an effort to reduce construction waste, WRNS renovated two existing buildings on-site while reusing the materials of the remaining buildings as the foundation of the two-story CLT structure. Over 345,000 square feet, or 2,400 tons, of CLT panels are used throughout the campus, representing more than half of the project’s total structural components.
The new, low-lying structure was designed to complement its natural surroundings through the addition of an occupiable living roof, a series of interior courtyards, and on-site trails that lead to nearby Stevens Creek. Every workspace within the building will have direct access to an outdoor space while allowing its occupants to precisely control airflow, temperature, and lighting within their individual working environments with minimal energy use.
Construction began in December 2017 and is expected to be completed by fall 2020.