Mass Timber a Main Feature to Sidewalk Labs’ Massive Master Plan

Sidewalk Labs’ Master Plan envisions vibrant outdoor space that would be accessible year-round. | Image courtesy Sidewalk Labs

Sidewalk Labs, in collaboration with design firms Snøhetta, Michael Green Architecture (MGA) and Heatherwick Studio, is proposing a $1.3 billion master plan set to turn a portion of Toronto’s industrial waterfront into a smart, digitally connected city prototype that would use engineered wood as the primary building material. If successful, it will be the first neighborhood constructed entirely from mass timber, with Sidewalk Labs calling for all buildings in its plan to be built with the naturally renewable, environmentally sustainable material. If given the greenlight, the Google-backed subsidiary plans to invest up to $80 million in a mass-timber factory in Ontario to help boost supply and jumpstart production of mass-timber products. The factory would fabricate two products: cross-laminated timber (CLT) structural panels and glued-laminated timber (glulam) beams, both used extensively in Sidewalk Labs’ concept designs.

A Master Plan Made of Mass Timber

A 521-page document, titled Toronto Tomorrow: A new approach for inclusive growth, spells out in vivid detail a futuristic vision of an urban mixed-use community—dubbed Quayside—complete with adaptable lofts featuring flexible walls, co-living spaces and shared equity units to help make the prospective housing more affordable.

The Quayside Plan makes the case for all buildings to be built with mass timber. While most cities currently use steel and concrete for taller buildings, the proposal points out, that comes at a cost:

“In Toronto, steel prices rose 16 percent in 2017 alone, and [buildings constructed out of steel or concrete] are difficult to produce, assemble, and transport, leading to lengthier, costlier, more disruptive construction projects,” adding they also “bear a steep environmental cost.”

In contrast, mass timber offers numerous advantages, including a smaller carbon footprint, faster construction times and something the project looks to really take advantage of—factory-based modular and prefabricated construction that can be assembled like a kit-of-parts.

A Master Template for Mass Timber

The master plan also sets out mass-timber design specifications for different building heights. Structures that are 10 stories and under are to be constructed using CLT panels while those 10 to 20 stories will use glulam post-and-beam construction. The plan also contemplates mass-timber towers as high as 30 stories using experimental construction methods.

All this upfront planning is intended to help buildings go up faster. So much so, the design team estimates that it can reduce costs and speed up construction time by up to 35 percent.

But quick and nimble construction isn’t the only expected benefit of this streamlined process. Likening it to a “library” of customizable building parts, each component could be pre-reviewed by the city helping to reduce overall uncertainty in the construction and permitting process. According to the plan, this approach could cut unnecessary waste, limit neighborhood disruption and improve site safety, all the while enabling architects to create entirely different and unique designs.

Snøhetta proposes a mass-timber housing development arranged in a semi-circle raised up by stilts and looking down on a public plaza. | Image Credit: Snøhetta

Maximizing the Modularity of Mass Timber

This last point is demonstrated in the distinctive approach each firm has taken in a series of conceptual designs, each their own interpretation of this library of mass-timber components.

Charlotte Bovis, project leader for Heatherwick Studio, admits at the onset their team contemplated whether buildings created using a repetitive modular mass-timber construction system would still be expressive and original.

Her answer was a resounding yes.

“In fact, using the system freed us from the distractions of ‘how’ and allowed us to focus on a design driven by the specifics of the site: the need for an intimate human scale intertwined with the public realm and a vibrant waterfront,” says Bovis whose firm’s design envisions mid-rise wooden towers marked by projecting circular balconies and ground-level gothic arches.

As Michael Green of MGA sees it, “designing with the toolkit allows us to create a diverse range of public and private spaces that enhance the quality and value of our built environment. These new neighborhoods, composed of wood, natural materials, and garden spaces, strengthen our connection to our homes, communities, and environment.”

MGA’s residential scheme presents a pedestrian-oriented arrangement of interconnected timber towers, with catwalks and balconies connecting to public gathering and green spaces.

Taking advantage of the flexibility and modularity of the mass-timber systems, Norwegian firm Snøhetta proposes a housing development arranged in a semi-circle raised up by stilts and looking down on a public plaza.

Throughout the plan, artistic renderings depict vibrant intimate walkable public spaces, alongside the active assembly of mass-timber buildings—a subtle nod to the fact that such prefabricated wood structures can be built quickly with smaller site crews and quieter construction.

Heatherwick Studio envisions residential timber towers adjacent to public spaces active in all seasons. | Image Credit: Heatherwick Studio

A Material as Strong and Fire-Resistant as Concrete

Confidence in mass timber as a safe, eco-friendly building material is unwavering with the proposal stating it is “a material every bit as strong and fire-resistant as concrete or steel but far more sustainable —including record-setting buildings of around 30 stories.”

The Quayside Plan is now before Waterfront Toronto for consideration. If approved, city and other government agencies will be the next hurdle for this ambitious master plan. A complete timeline for construction of the project has yet to be established.

A full version of the plan is available on Sidewalk Labs’ website.