Attached housing key to a clean, dynamic city
Renovating single-family homes isn’t the answer when it comes to reducing carbon emissions. Instead, Vancouver needs to commit to building environmentally efficient, four- to five-storey row housing. This will reduce overall emissions while creating vibrant neighbourhoods that increase housing supply.
Last year, we published a study that looks at the carbon implications of tearing down single-family homes and replacing them with newer, more efficient structures of the same type. What we found surprised us. For a typical wood frame, single-family home in Vancouver, carbon payback averages 168 years.
The carbon payback for new structures drops to around 30 years after 2025, assuming that the City of Vancouver implements the aggressive performance targets they have identified. But under current performance standards, each time we tear down a functioning home and replace it with a new one, we increase our overall carbon emissions.
The carbon payback period for renovations to existing single-family homes is unlikely to be much better. Older wood frame houses in Vancouver are often built without insulation, basements, or seismic protection. Deep renovations to these structures often require replacing all but the shell of the building, which is similar to tearing houses down and rebuilding from scratch. Preserving heritage structures commemorates our shared history, but it’s a cultural rather than an environmental priority.
In light of these findings, it’s unfortunate that our study has recently been cited by Vancouver Coun. Colleen Hardwick in a motion that suggests limiting new construction in favour of renovation. This motion stems from a misunderstanding of our research.
In Vancouver, homes are being torn down and replaced for reasons that have nothing to do with environmental performance and everything to do with economics. Put simply, a cheap house constructed on an expensive building lot has little chance of surviving when the property changes hands. Radically increasing land values produce a teardown cycle as new owners demolish existing homes and rebuild commensurate with the overall value of their property, resulting in spiralling carbon emissions.
Rising property values also makes it likely that today’s new single-family home is next year’s teardown. Replacing one efficient home with another offers diminishing environmental returns: the carbon payback in this case can easily stretch to 500 years or more.
As long as we keep replacing carbon intensive single-family homes with more of the same, we can’t use the teardown cycle to address the overall carbon emissions of buildings or affordability concerns. Even with laneway initiatives and secondary suites, single-family zoned areas of the city have barely maintained their population.
Instead, we need to loosen zoning so that single-family homes can be selectively replaced with ecologically and economically sound, fourto five-story row houses and townhomes. This will diversify our housing options, reduce carbon emissions, and create dynamic neighbourhoods like those found in Berlin, Paris, and Montreal. Attached housing in these cities allows more people to live in proximity to jobs and amenities, decreasing their reliance on cars and accommodating families. Designing similar housing for Vancouver can do the same here.
Vancouver is entering a new phase of urban development. Providing sustainable housing to one million new residents moving to our region by 2050 will require letting go of older suburban models of development built on carbon-intensive single-family homes punctuated by clusters of glass towers.
Designing high-performance attached housing using laminated timber and other emerging structural products made of sustainable timber grown in B.C. can sequester carbon, add valuable jobs to the B.C. economy, and deliver on Vancouver’s green ambitions. The higher value of these structures also will decrease the likelihood that they’ll be torn down before their carbon debt is paid off.