Embodied Carbon 1

Embodied Carbon in buildings refers to “greenhouse gas emissions arising from the manufacturing, transportation, installation, maintenance, and disposal of building materials”, according to the Carbon Leadership Forum. This is distinct from Operational Carbon which are the ongoing emissions generated due to the usage of the building each year.

How relevant is Embodied Carbon for our 1950s SFD renovation?

To help answer this question, we are working with Energy Efficiency and Life-Cycle Consultants Carbon Wise. We plan to estimate how many tonnes of CO₂ will be emitted to construct our building, and how much we save by renovating instead of a building new – watch this space for the full report.

From the results we have so far, the carbon cost of a complete teardown and rebuild according to our plans would be about 40 tonnes (note that our renovation cost will be less, this is the worst case). This compares to operational emissions of the existing building which are 8 tonnes per year (it’s a gas powered, leaky 1950s house). So the embodied carbon spent on a net zero rebuild would be paid off in about 5 years. Or, assuming a 50 year life for our old building, it’s operational emissions of 400 tonnes would be 10 times larger than the embodied carbon spent to build a new efficient building.

Note that as we decarbonize our grid and building codes mandate net zero, the fraction of embodied vs operational emissions from the building industry is expected to increase to as much as 40-50% (e.g. Stantec, Architecture 2030). However, this refers to a future scenario where operational carbon emissions have already been drastically cut, and with our current renovation rate of 1% of year, is likely many years out (i.e. 2050).

Should we care about embodied carbon in our renovation? Yes. 40tCO2 is still a large amount, approximately 3 times the per capita emissions for Canada. By retaining elements such as the foundation walls, footings & slab and floor/wall studs, we can keep carbon-intensive and high value materials in use for longer. Working with a deconstruction company allows us to repurpose the rest of our materials for a next life.

But from the perspective of lifetime emissions, and for an inefficient and leaky building such as ours, operational carbon dominates. Getting gas guzzling houses like ours “off the road” (eliminating operational carbon) is the first task, as the emissions reduction potential is an order of magnitude greater.

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