Architect: AMLGM | Photo: Sierra Institute for Community and Environment

California’s first full CLT building opens in Plumas County

Meet California’s first full CLT constructed building: the Biomass Boiler Building in Plumas County. The structure leverages the inherent thermal properties of cross-laminated timber to generate heat and energy to the Health and Human Services Department in Quincy, CA.

Project Details

The industrial Biomass Boiler Building houses an innovative biomass system using organic and sustainable waste material to generate heat for the Health and Human Services Building as an alternative to fossil fuels. The boiler is only the second of its kind in the U.S.; it is a community-scale, biomass boiler unit that runs on hog fuel, a coarse woody material generated as a byproduct directly from forest restoration and management activities.

Wood Use

The architectural design of the building showcases the use of mass timber with completely exposed surfaces on the interior, and exposed wood underneath the roof eaves. The vertical surfaces of the exterior of the building were clad to protect the wood from the elements, UV, moisture and to provide additional fire protection.

Originally, the Biomass Boiler Building structure was planned to be constructed with a prefabricated metal building system. Plumas County officials and the Sierra Institute decided to take the project in another direction to demonstrate the strengths and benefits of building with wood while also incorporating Plumas County’s abundant natural timber resources.

Camille Swezy, Wood Utilization Program Lead of Sierra Institute, remarked, “The community of Quincy and Plumas County officials are very pleased with the new Biomass Boiler Building constructed entirely of CLT, now housing an innovative biomass heating system. Timber and wood products development is deeply engrained in Quincy’s roots, and the community is now thrilled to have a demonstration of wood utilization in a practical small-scale application.”

Seismic + Fire Performance

The Biomass Boiler Building was constructed using CLT panels for the complete structural system to resist gravity and lateral forces, such as wind or a seismic event.

“There was no precedent in California for a project that used CLT as the seismic-force resisting lateral system”, Associate Principal, Erik Kneer of Holmes Structures explained. “We developed a strategy in close coordination with the Plumas County building official that combined precedent in other states with a conservative yet responsible interpretation of the code. We provided a pathway to approval of the project without burdening it with an overly expensive or time-consuming solution.”

Installation

A key advantage of CLT construction is the reduced installation time and crew size required to lift, set and screw the engineered lumber panels into place. The time on the project from concept development to substantial completion of the Biomass Boiler Building was less than a year, with rapid delivery on design, approvals and construction being critical to have the building closed and protected before the 2017/2018 winter season. Erection of the primary superstructure occurred over just a one-week period in December of 2017.