Underground parking garages are not "sustainable"

The word "sustainable" has been debased beyond recognition, but the University of British Columbia takes it to new depths.

Sorry, no images of the parking garage underneath. Image: Olson Kundig

The press release from the University of British Columbia, Okanagan campus, positively gushes sustainability (my bold facing of the word) in describing a proposed groundbreaking “tanked” parking garage, which “marries sustainability with structural ingenuity.”

UBC Okanagan is redefining urban infrastructure and sustainable construction practices in Kelowna with the construction of a state-of-the-art underground parking garage for UBCO Downtown.

And what makes it sustainable?

It employs an innovative ‘tanked’ design that will use a special waterproof concrete mix to accommodate the city’s high water table. Unlike conventional construction where water accumulation around the foundation is drained or pumped away—potentially carrying away vital sediments and destabilizing surrounding soils—the tanked design keeps the water and soils in place, ensuring hydrostatic pressure balance.

They are also proud of the way they are dealing with the dirt.

In line with UBCO’s commitment to sustainability, the fill extracted during the parkade’s construction will be transported to the main campus, providing necessary and high-quality material for slope stabilization and aiding in the area’s future utilization—all while minimizing waste generation and saving on future trucking emissions.

“This move exemplifies our dedication to minimizing waste and optimizing resources during the construction process,” adds Rob Einarson, Associate Vice-President for Finance and Operations at UBC Okanagan. “It’s a testament to our commitment to sustainability and our responsibility as a steward of the environment.”

He also notes the underground parking is one of several sustainability aspects considered with the downtown project.

It is not the first time a parking garage has been called “sustainable;” way back in 2007, I wrote about the first LEED-certified parking garage in Santa Monica, noting that by the nature of its function, a parking garage could not be described as sustainable, “even if it was made from site-grown bamboo and ventilated by flapping butterfly wings."

And that was before I had ever heard of embodied or upfront carbon. Here we are in 2023, and UBC is describing a four-level concrete underground garage as sustainable when in fact, they are massive upfront carbon icebergs that lie beneath the surface.

While teaching at John H. Daniels Faculty of Architecture, Landscape, and Design at the University of Toronto, Kelly Alvarez Doran studied the impact of underground parking garages and found:

“Foundation works, underground parking structures and below-grade floor area have disproportionate impacts on a project’s embodied carbon. For mid-rise and high-rise structures, between 20 to 50 percent of each project’s total volume of concrete was below grade.”

I sent Kelly an article on the UBCO garage and asked what the usual rule of thumb is for the carbon footprint of a parking space and he told me “20-30 tonnes per parking space. And add another 10-15 for the bath-tubbing.”

Another study, Estimating the carbon contribution of the construction and operation of parking spaces in the City of Vancouver looked at five buildings and came up with a wildly divergent conclusion that “The impact per parking space varied from 5 tonnes to 84 tonnes.” It also came up with operating carbon emissions of about 60 kg of CO2 per space per year, running the lights and fans.

So our 262-space Kelowna parking garage probably has an upfront carbon footprint of 40 tonnes per space or 10,480 tonnes of CO2. The average Canadian car emits 200 grams of CO2 per kilometre, so that is equivalent to a car driving 52.4 million kilometres, or 680 times to the moon and back.

And parking garages are like baseball fields in Iowa; if you build it, they will come. Like wider roads, parking garages induce demand, with studies showing that “parking provision in cities is a likely cause of increased driving among residents and employees in those places.” So we can add the carbon footprint of the cars to the calculation.

So please, University of British Columbia, do not call your parking garage construction sustainable. The word has been debased beyond recognition already, but you have taken it to new depths. In my first Sustainable Design class each year at Toronto Metropolitan University, I discuss what a terrible name it is, showing examples of the hilarious or appalling misuses of the word; this will be my new favourite poster child.

As an aside, the carbon per parking space calculation should be done for the $650 million underground garage being built by taxpayers all over Ontario to serve the silly spa being built at Ontario Place. Its 2118 parking spaces will probably have a footprint north of 85,000 tonnes of CO2, equivalent to putting Doug Ford in a car and driving him to Mars, which would be a good plan.