Reuse-Recycle-Reduce at the Grove

Instead of building a new house from scratch, we relocated an existing house and shaped it through a simple framework: Reuse–Recycle–Reduce at the Grove.

Originally built in South Surrey in 1978 and updated in 2011–12, the house was facing demolition as part of a redevelopment project. Instead of being sent to landfill, it was relocated by Nickel Brothers. We purchased the house and brought it to Mayne Island, where it was renewed and carefully adapted for its new life at The Grove.

Relocating and reusing an existing home is one of the most effective ways to reduce the environmental impact of construction. Much of that impact is embedded long before anyone moves in, in the form of embodied carbon (carbon dioxide equivalent, or CO₂e): the emissions created when materials like concrete, lumber, steel, glass, and wiring are manufactured, transported, and assembled.

Current studies of residential construction in British Columbia suggest that a typical low-rise wood-frame house carries roughly 75 to 120 kilograms of embodied carbon per square foot, depending largely on foundation type, envelope performance, and material choices. For this analysis, we used a conservative midpoint of 100 kg CO₂e per square foot, or 0.1 tonne CO₂e per square foot.

According to that baseline, had we built the entire 3,200 square foot house from scratch, the structure would have 320 tonnes of embodied carbon:

3,200 sq ft × 0.1 tonne CO₂e per sq foot = 320 tonnes of CO₂e

So this will be our baseline from which we apply carbon "credits" and "debits" through our Reduce-Reuse-Recycle approach.

Reuse: relocating instead rebuilding

Had the house not been relocated, its estimated 67 tonnes of material could have ended up in the landfill, where construction and demolition debris already accounts for roughly a 25-30% of all waste by weight. By relocating the existing 1,600-square-foot house from the Lower Mainland to Mayne Island, we gained an embedded carbon "credit" since we didn't have to rebuild that portion.

But reusing a house does not preserve every material. We had to build a new foundation, we replaced the siding, the roof, and we created a primary bedroom and ensuite where the garage and mechanical room used to be. This required new framing, a new floor system, electrical, plumbing, insulation and finishing work.

Multiple studies of building reuse and renovation find that upgrading an existing home typically reduces embodied carbon by more than half compared to building new, because much of the original materials are preserved and do not have to be re-manufactured. For this reason, we conservatively assumed that The Grove retained about 75% of the original embodied carbon through relocation and renewal:

1,600 sq ft × 0.1 tonne CO₂e per sq foot × 75% = 120 tonnes of CO₂e

Compared to a full new build estimated at 320 tonnes of embodied carbon, relocating and renewing the house resulted in approximately 237 tonnes of embodied carbon, for a net savings of 83 tonnes, as outlined in the carbon ledger below:

Click to enlarge

Each component was estimated using typical embodied carbon intensities (tonnes CO₂e per sq ft, per cubic metre, or per activity) drawn from Canadian and North American life-cycle assessment studies, then rounded conservatively.

This analysis looks only at embodied carbon, the emissions created by construction and renovation, not the emissions from operating the home over time. Still, it can be helpful to translate the carbon savings into something more familiar.

A typical all-electric home in British Columbia emits roughly 4–5 tonnes of CO₂e per year from heating, hot water, and electricity. At 75% annual use, that drops to about 3–4 tonnes per year. Using the upper end of that range for a conservative estimate, the 83 tonnes of embodied carbon avoided is equivalent to nearly 21 years of household operation:

83 ÷ 4 = 20.8 years

We didn’t make the house “carbon neutral,” but it’s interesting to think that the embodied carbon we avoided by moving and renovating it is roughly equivalent to about 20 years of typical household operating emissions.

Finally, reuse at The Grove went beyond the house itself. We kept and reused the major appliances that came with the home, including the refrigerator, oven, stovetop, washer, dryer, and dishwasher, avoiding the embodied carbon of manufacturing replacements. Furnishings and equipment are also sourced primarily through local reuse, with items purchased at Mayne Island's Thrift Store and on Marketplace whenever possible. Extending the life of what already exists is often the simplest and most effective sustainability choice.

Recycle: giving materials a second life

As mentioned before, moving the house meant that not everything could be reused in place. The original aluminum siding was damaged during transport and had reached the end of its useful life. Rather than sending it to landfill, all of the aluminum siding was recycled, allowing the material to re-enter the supply chain with a fraction of the energy required to produce new aluminum.

Reduce: reducing well water use with rain catchment

Water use is another area where reductions are possible. At The Grove, rainwater collected from the roof is used to supply all the toilets.

Over the past 18 months, we used 30,780 gallons of well water, while 7,560 gallons of rainwater were used exclusively for flushing. That means roughly 20% of our total water use came from rain rather than the aquifer. While it took extra planning and investment, the setup meaningfully reduced demand on local groundwater, which is critically important for Mayne Island.

To conclude, sustainability was less about doing everything new and more about making careful choices at the Grove. By Reusing an existing house and its appliances, Recycling materials that could not be saved, and Reducing ongoing demands on energy and water, we meaningfully lowered the project’s environmental footprint compared to a full new build.

Sources:

• https://embodiedcarbon.climateresilienthousing.org/downloads/Build-Change-Carbon-Executive-Summary-compressed.pdf

• https://firstgreen.co/revitalizing-buildings-a-comprehensive-guide-to-reducing-embodied-carbon-emissions-through-renovation/

• https://carbonleadershipforum.org/lca-benchmark-database/

• https://en.wikipedia.org/wiki/Adaptive_reuse