4 cottage building materials that are better for the environment

Producing concrete and Portland cement contributes up to nine per cent of all human CO2 emissions. But there is an easy alternative to standard Portland cement. Portland limestone cement just has more limestone—it costs the same, performs the same, and is widely available. Plus, making it emits 10 per cent less carbon. That’s significant because concrete is by far the most widely used building material. New products, such as Lafarge Canada’s ECOPact, promise up to 90 per cent reduction in embodied carbon.

Insulation materials, including fibreglass batt, spray foam, and extruded polystyrene, vary in embodied carbon. Wood fibre insulation actually offsets emissions—it stores carbon— and it can be formed into batts, rigid boards similar to foam sheets, or loose-fill insulation that can be blown into cavities. Downsides? Wood fibre insulation can be more susceptible to deterioration if not installed correctly, and it can be pricier and harder to source—for now.

Hempcrete combines the woody stems of the hemp plant with lime-based binder and water. It’s insulative, fire-resistant, breathable, and deters insects and rodents—and it’s carbon negative. It doesn’t do well underground, where it may get wet, and it can’t be used for load-bearing walls—at least not on its own. Calgary-based Just BioFiber makes interlocking hempcrete bricks, supported by an internal load-bearing frame. They perform like concrete blocks, but they look like Lego and promise to be almost as quick, easy, and fun to build with.

There are a lot of pros to steel roofing—it lasts a long time without deteriorating—but making it uses a lot of energy. Asphalt shingles—surprise—actually have a pretty good carbon record, with less than a quarter of the embodied carbon of steel panels. Asphalt shingles also cost less upfront and can be found at just about every hardware store.