Mass timber

At Gradient Canopy, where we’ve attained the International Living Future Institute (ILFI) Living Building Challenge (LBC) Materials Petal certification, finding ways to incorporate non-toxic and ecologically restorative materials was paramount. For this reason, we explored ways to integrate sustainably sourced mass timber into the building to tap the regenerative, carbon-sequestering properties of wood.

Mass timber is a construction technique utilizing wood compressed together to create columns, beams, walls, floors and roofs in a way that can reduce embodied carbon compared to traditional building approaches. In the end, mass timber figures prominently within the building, and what we learned here has informed other construction projects at Google.

We have been interested in the potential of mass timber for some time because it promotes healthier, more productive, visually inspiring workplaces through its biophilic qualities. Biophilia is about integrating nature with design to create spaces where people thrive, and being able to incorporate exposed wood elements inside the building not only reduces the need for applying additional materials such as coatings and paint, but also helps people feel connected to nature even when inside. So when we started the design of Gradient canopy, we initially explored the possibility of having the entire structure of the building utilize mass timber and found the long spans we wanted were not possible, however, we were still able to incorporate wood for some of the structural elements inside the building.

At Gradient Canopy, mass timber elements take the form of cross-laminated timber (CLT) members, a form of engineered wood made from gluing together multiple layers of solid-sawn lumber to achieve better structural rigidity. We started with CLT as the formwork (molds into which concrete is poured) for the second level concrete floors, where it provides composite strength. We integrated it in such a way that, rather than being removed and disposed of as is typical practice after the concrete sets, the CLT is left in place to double as exposed wood ceiling for the ground floor spaces and guardrails around the interior courtyards. Wood is also used for the doors and door frames throughout the building, particularly for meeting pods and conference rooms. For these, the team was able to work with the vendor to earn a Declare label certificate for the entire door assembly, helping us prioritize building materials that demonstrate safer chemistry to create a healthy indoor environment.

When we started the design of Gradient Canopy, CLT had not been used for structural elements at this large scale in Mountain View yet. Therefore, we made a full-scale mockup of the CLT elements during that early phase and invited city officials to view and inspect the structure firsthand to ensure it met their requirements. Building physical prototypes helped us work together to collectively come to a solution that met city requirements, while also driving towards more sustainable ways of building.

We also ensured that the wood we incorporated into the Gradient Canopy building was sustainably sourced. Over 99% of the new lumber used at Gradient Canopy (both temporary and permanently installed) was procured from responsibly managed forests certified by the Forest Stewardship Council (FSC). It’s unusual to procure FSC-certified wood for temporary uses such as formwork, which can then be re-used for future projects. However, knowing that temporary wood accounted for a large percentage of the total lumber on the project, it was important to account for the temporary wood uses as well. Prioritizing FSC-certified wood doesn’t just mean that the lumber we’re using is responsibly sourced, it also means that we’re supporting larger efforts toward reforestation. Ultimately, we believe healthier and responsibly sourced materials are not only fundamental to sustainable development, but also to the creation of a broader circular economy that’s consistently regenerative and restorative.

Now the mass timber research that we performed during the design of Gradient Canopy is informing the design of other Google buildings. For example, in Sunnyvale, California, we just opened 1265 Borregas which is our first ground-up mass timber building. It's projected to have 96% fewer embodied carbon emissions than an equivalent steel and concrete structure, factoring in sequestration. It’s just one example of how learnings at Gradient Canopy have bolstered our efforts towards designing more sustainable and healthy buildings.