How to design an eco-cottage

Published: June 19, 2019

Paul Orenstein

You can minimize your impact when building or renovating a cottage using these tips that architect Ian MacDonald used when designing his own cottage:

Site the cottage gently.

At one spot, the steel crossbeam of the large front deck sits perfectly flush with the knob of the Canadian Shield on which the whole structure stands, allowing a simple half-step from deck to ancient rock and making a seamless transition from built to natural environment. “It’s Planet Earth,” Ian MacDonald says. “You should work with it.” This cozy fit of rock and steel is one of his favourite features, testament to the care he took to avoid levelling the lot or otherwise rearranging the landscape to fit the design. The building perches lightly on top of the rock on eight concrete piers pinned directly into the rock.

Use restraint when it comes to size.

Ian advocates frequently for appropriate size and scale with his cottage owners’ association and beyond. As part of a design survey, he learned that 87 per cent of historic cottages on Go Home Bay were less than 1,800 square feet in size. When he replaced the old 1,100 sq. ft. cottage on his own property, it was no accident that his design combined a 1,400 sq. ft. interior with 400 square feet of exterior space.

Harness the sun.

When we talk about sustainability and the sun, we tend to think immediately of solar panels. There are none on Ian’s cottage, but its clever use of natural light and shade use the sun in cheaper and simpler ways. Just below the roofline, a line of east-facing clerestory windows, which are windows set high in a wall above eye level, draw light into the west-facing rooms (the master bedroom and the bathroom) and provide ventilation on warm summer days. Evergreen trees shield the north side of the cottage and give shade in summer when the sun is high. There are more coniferous trees on the south side, so fall and winter light reaches the cottage directly. This smart approach to sun and shade helps to warm and cool the cottage when each is needed most.

Hoard the heat.

Ian designed his cottage for year-round use, so he included three cast iron woodstoves and a cast iron cookstove. Two of the woodstoves—a modern, ultra-high-efficiency stove and a compact, stylish vintage stove made by Norwegian company Jøtul—provide most of the heat for the cottage. And they do so using little wood, because both are mounted in nooks within a concrete slab wall in the centre of the cottage, which absorbs and stores the lion’s share of their heat. This is a design technique known as “thermal massing.” The heat absorbed by the slab radiates slowly into the interior of the cottage over the course of the day, providing a huge boost to the overall efficiency of the system and reducing the dramatic swings between too hot and too cold associated with woodstoves.

Plant the roof.

“Really it’s the roof that is the defining characteristic of the place,” Ian says. Its flat, modern plane is a direct rebuke to the Ranger Smith towers down the coast. The low profile is in keeping with the cottage’s heavy emphasis on simple, unobtrusive, less-is-more elements. But it’s the roof’s blanket of elegant, colourful native moss, plants, and grasses that sets it apart from a typical urban modernist box and helps to keep the cottage cool in summer. The greenery also protects the roof from UV exposure, which is what causes the most damage to roofs, and integrates the cottage with its surroundings, making it all but invisible from the water.

Blur inside and out.

The west wall of the cottage, which opens on to the deck, has a unique feature: the section enclosing the living room and the master bedroom was constructed as a series of oversized patio doors that slide away to one side, eliminating the barrier between interior and deck. In essence, the entire exterior wall of the living room is removable, with screens to keep the bugs out and pull-down shades to block the sun. Despite the size of the panels, it’s a quick and easy transformation that opens the whole cottage to the breezes and makes the space feel far larger than its dimensions.

Remember: small is beautiful.

The two guest bedrooms are exactly as wide as a standard queen-sized bed, but they feel larger—each has a window running the full width of the space at the eye level of someone reclined in bed, providing a vast view over the water. Like so many other details in the building, the balance between interior coziness and exterior vastness is just right.

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