At Carbon Wise, we worked on over 25 Life Cycle Assessments (LCAs) in 2024, covering a range of project sizes, stages, and construction types. With embodied carbon in buildings now in the spotlight, this gave us a chance to step back and ask: what’s working, what’s not, and where can we do better?
Not All Emissions Are Equal
Our projects varied widely in scale — from 3,000 m² up to over 100,000 m². But what mattered more than size was emissions intensity (kg CO₂e/m²).
Emissions intensity measures the amount of carbon emitted per square metre of building. It accounts for the total embodied carbon divided by the usable floor area — giving a fair way to compare buildings of different sizes.
-
Average intensity: 363 kg CO₂e/m²
-
Best project: 135 kg CO₂e/m²
-
Worst project: 614 kg CO₂e/m²
-
Most fell between 306 and 433 kg CO₂e/m²
That’s a wide spread, showing that the difference isn’t just what we build, but how we build it. Structural systems, assemblies, and material choices drive carbon outcomes far more than floor area alone. No surprise here: the top-performing project was a six-storey residential built with wood stick framing.
Rezoning Projects Tend to Have Higher Carbon
We noticed that projects assessed at the rezoning stage often had higher emissions. This isn’t surprising:
-
Early-stage designs are bulkier and less optimized
-
There’s less clarity on exact materials and systems so we often have to default to the National LCA Guidelines or City of Vancouver Guidelines.
-
Teams are still deciding what’s even feasible
Some of our highest-carbon LCAs came from rezoning applications, where material volumes (especially concrete) were likely overestimated to account for design uncertainty. Structural engineers also tend to be hired later in the process so, at rezoning stage, they often haven’t had a chance to weigh in yet.
But Rezoning Is Still the Right Time to Start
Doing an LCA at rezoning isn’t a waste, in fact, it’s necessary. It sets a baseline, flags high-carbon systems early, and helps teams make better choices while there’s still time to change direction.
But it can’t stop there.
As drawings evolve toward Building Permit, new materials get added and quantities get refined. That’s when total embodied carbon can jump. If the LCA is treated as a checkbox, teams risk unpleasant surprises at BP when emissions are suddenly too high.
LCA Should Guide Design, Not Just Measure It
To avoid those surprises, teams need to treat LCA as a design tool, not a final report.
-
Use it to compare systems early
-
Re-run it when key materials change
-
Tie it to cost and procurement, not just compliance
This is where an integrated design approach comes in. Bringing in LCA insights throughout the process (not just at rezoning, and not just when the model is “final”) helps keep projects on track for both performance and feasibility. When done properly, it can also reduce material costs by identifying overdesign early and supporting smarter choices.
Looking Ahead
This year’s data confirmed what we’ve long believed:
Carbon performance is a design outcome.
It’s shaped by decisions, not just metrics.
By embedding LCA into early conversations and revisiting it at each major milestone we can avoid trade-offs, reduce risk, and build better.
Curious about your own project’s embodied carbon?
Reach out to our team! We’re happy to take a look, wherever you’re at in the process.