Green design features

Before we get too far into the construction and start filling this space with endless pictures of backhoes (who doesn't love backhoes?), we thought it might be a good idea to put information in here about some of the features we’re most excited about.

When we decided to build, we knew we wanted to build the most energy-efficient house we could afford. Our decisions about the location, footprint and envelope of our house were among the most significant we made in terms of reducing our impact on the environment.

The big three

Location: We wanted to find a location that would be close enough for us to walk to work. Proximity to skiing, hiking trails, and canoeing was also on our wish list. We work in the market, and like to ski, hike and canoe in Gatineau Park, so downtown was the obvious choice. Land downtown, however, doesn’t come cheap. Once we found our lot in New Edinburgh and fell in love with the neighbourhood, we decided we were willing to make the necessary sacrifices to keep our construction costs down and try and compensate for the difference. This decision set the framework for all of the other decisions we had to make.

Footprint: The size of the house will also help us keep our energy use, and associated costs, down. At about 1,950 square feet, we’ll have as much space as we’ll need. Instead of building out, we’re building up. The design includes two stories in the front, and three in the back.

Envelope: To get the biggest bang for our buck, we invested the greatest proportion of our budget in everything that separates the house from the elements — the foundation, basement slab, walls, windows, doors, ceilings, roof and insulation. For our foundation and basement walls, we chose insulated concrete form (ICF) blocks. Concrete is poured into blocks between two layers of foam insulation. The blocks stabilize the interior temperature and keep the humidity out of the basement. They can also get the insulation values up to
R-50, although this is difficult to measure precisely. The higher the insulation value, the lower the energy use and cost for us. Our low-emissivity (low-e), argon-filled windows will help to keep the heat in when it’s cold and out when it’s hot. We also opted for the Cadillac of insulation: spray-in foam. The soy-based foam we picked expands in place to fill all the nooks and crannies and makes for the tightest possible house. The vapour barrier is built in, so we’ll save a bit on material costs. The house will be finished partly in brick and partly in siding. The fibre-cement siding material we chose is made out of wood pulp, cement, sand and water, is very durable and low-maintenance, and allows air circulation and drainage. Finally, we picked a durable steel roof to make sure we won’t need to replace it anytime soon. In all, the envelope is our biggest expense, but it’s the feature that will bring us the highest returns.

Other green stuff

Materials: We will use wood certified by the Forest Stewardship Council (FSC); water-based adhesives and finishes; paints, caulks and adhesives with no or very low concentrations of volatile organic compounds (VOCs); and, where we can, locally harvested or manufactured materials.

Water conservation: A rain barrel on our second-floor deck will collect rainwater for us to use to water our plants. We’re also planning on going with native and water-free vegetation for our landscaping (xeriscaping). Some people think that makes us lazy gardeners, not environmentalists. Ah, well.

Site protection and waste management: Protecting the site and managing construction waste were important considerations for us, and are built into our contract with our builder. The crew will stockpile topsoil onsite and cover it to prevent erosion, be as kind to the existing vegetation as they can be, and recycle as much of the construction waste as possible. They’ll use off-cuts where they can as blocking, bracing, or strapping to reduce waste. They’ll also collect, sort and store all of the waste materials for recycling. Leftover untreated wood will be mulched and used for ground cover. Metals (steel, aluminum, etc.), paper, cardboard, plastic bottles, metal cans, and drywall will be recycled.

Heating: We’re going with radiant floor heating. Other than the envelope, this was our biggest ticket item. A natural-gas-fuelled on-demand hot water boiler will supply heat to the radiant floor and hot water system. Because radiant floors distribute heat evenly, we’ll be able to keep the thermostat lower than we would with a forced air system (some say two to four degrees lower, but if John has anything to say about it, it will be more like five to ten degrees), which means lower energy costs. Some people estimate that we will save between 10 and 40 per cent on our energy bills with radiant floor heating. Sounds good to us. Warm, comfortable floors and better air quality sound very nice, too.

Appliances and fixtures: This part was easy. Energy-efficient appliances and dual-flush toilets are the way to go. John spent a lot of time reading the results of dual-flush toilet tests, which are conducted using soy-based feces simulants shaped into realistic, uniform shapes. Yes, you read that right. I was happy to leave that research to him.

Future possibilities: As much as we would have liked to, we couldn't do everything we wanted right away. A few features will have to come later. Among these is a solar hot water pre-heating system and insulated storage tank. A geothermal heating system may also still be in the cards; it's perfectly compatible with radiant floor heating.
*A note on geothermal: this was a feature we were very sorry to have to cut out, but after much research and calculations, we decided it just wasn’t worth the expense right now. With our envelope the way that it is, the law of diminishing returns told us it just doesn’t make sense to invest so much (about $30,000) in a heating system when our heating needs are so dramatically reduced. However, the law of really cool green technologies screamed “Go for it anyway!” In the end, we made the tough call to nix it, for now. Finally, our builder’s going to lay the groundwork for a green roof, which we will install soon. Vegetation will add extra insulation to the roof on our third story, reduce run-off, and be very nice to look at, too.

For anyone interested in reading about green construction options, I’d recommend Your Green Home: A Guide to Planning a Healthy, Environmentally Friendly New Home, by Alex Wilson. It has a lot of very good information on site location, building materials, construction techniques, and more.