Sidewalk Labs is developing a raincoat for buildings

The Alphabet-owned company hopes to use this tensile structure, which attaches to building facades, to make being outside in extreme weather more comfortable.


Before central heating and air conditioning, cities looked very different–awnings and protective elements that would make the weather, both hot or cold, more bearable for people as they moved around outdoors. But as AC and heat have become ubiquitous, many of these external structures have disappeared from cityscapes.


Now, the Alphabet company Sidewalk Labs is experimenting with a radically new kind of awning in Toronto, where the company is building its first smart city development. Called a “building raincoat,” the flexible awning’s purpose is to increase people’s comfort when they’re outdoors by sheltering them from wind and rain. Ultimately, Sidewalk Labs hopes that the raincoat could get people to spend more time outside, even if it’s cold. Ultimately, the design could lower the energy needed to heat and cool the structures in the long term.

The raincoat was designed by Toronto-based firms RWDI, which specializes in climate engineering, and Partisans, which focuses on experimental, tech-driven architecture. The group debuted the tensile structure, which was derived specifically from RWDI’s analysis of how to mitigate wind and precipitation, over the weekend at Sidewalk’s Toronto office, 307. The raincoat, which looks almost like a futuristic tent made from a thin plastic membrane that’s pitched against the side of a building, will stay there for an entire year as the design team tests its performance to see if it measures up to their estimations.

[Photo: Sidewalk Labs]

According to Jesse Shapins, Sidewalk’s Director of Public Realm & 307, Toronto’s streets are only comfortable for about 30% of the year–and that’s no surprise, given that the Canadian city’s winters are long and brutally cold. According to RWDI’s analysis, the raincoat could potentially double the amount of time people could comfortably spend outside in the neighborhood. That analysis is based on the Universal Thermal Comfort Index, which takes into account environmental factors like wind, precipitation, humidity, and temperature, as well as other factors like what people wear.

The goal is to make people more comfortable as they participate in civic life on the streets starting earlier in the spring and later into the fall, extending what Shapins called “patio season” with more farmers’ markets, patio seating, and more public events outdoors. Shapins says that programming will be an important element of this goal, since the prospect of less exposure to the elements alone won’t necessarily get people outside–but a farmers’ market would. That’s why the prototype of the raincoat at Sidewalk Labs’s Toronto office will also have a public art component, with swirling projections that respond to their surroundings.

[Photo: courtesy Sidewalk Labs]

To design the raincoat, Partisans came up with a series of architectural concepts, which the climate engineers at RWDI then ran through computer simulations that modeled an average spring or fall day in Toronto and analyzed how the raincoat design would manage wind and sun. Through this process, the architects tweaked their design to maximize the performance guidelines that Sidewalk was looking for.

For Shapins, there’s an even greater purpose here: to design buildings that are more in tune with the environment.


“We’re looking to create this expanded, large gradient from indoors to outdoors that is much less about fixed moments where now I’m outside and now I’m inside, but is more of a spectrum of comfort,” he says. That could mean that the ground floors of buildings are more open to the outdoors–which would make them closer in temperature to the weather outside. If Sidewalk can successfully alter people’s expectations around indoor temperature on the ground floor, the company could use less energy for heating and cooling–contributing to its plan to be carbon neutral.

Shapins acknowledges that adding a structure like this to the outside of a significant portion of buildings would be far more expensive than a typical facade. But he also points out that cities like Toronto have extensive underground systems and glass facades connecting buildings that cost significantly more than the prototype Sidewalk is developing.

Ultimately, this is about what Shapins calls “community vibrancy”–a somewhat ineffable quality that you sense when you walk down the street of a thriving neighborhood. People are out and about, shopping, running errands, and walking their dogs. The streets seem to thrum with energy. While most cities come by this vibrancy organically, Sidewalk Labs is embarking on a project to engineer it.

About the author

Katharine Schwab is the deputy editor of Fast Company's technology section. Email her at and follow her on Twitter @kschwabable