A garden helped to shape a home renovation.

Since finishing the renovation on their house, Janelle and Tom Adams are not only watching their two young children grow. When the couple commissioned architect Mick Hellen of aardvarc to design an extension to the back of their 1950s house in Holland Park, they had an important question for him: “how do we overcome this blazing Queensland sun?”

His bold, green solution was to encase a two-storey extension to the rear of the house in a trellis over which deciduous vines would climb, re-using as many materials as possible from the demolished part of the existing house. “In the summer, the vines get dense and the leaves shade the structure and create an air barrier against the wall,” explains Hellen. “In the winter the leaves are off so more sun hits the wall.”

Fortunately, the Adams’ were adventurous enough to run with the idea. When their extension was complete, the family planted four varieties of vine and Trellis House began to take shape around them.

Rewind to the start of the six-month build (by Peterbuilt) and the Adams family’s two-bedroom house was about to expand to include a new open-plan living room, a spacious kitchen and dining room downstairs, and a master bedroom with ensuite bathroom upstairs. “We chose to renovate rather than knock everything down as we didn’t like the idea of bulldozing and dumping good materials that just needed a new lease on life,” says Janelle. “When the build started, everything that came off the house was kept and stored. There was so much timber!”

A key requirement was that the extension embraced the outside: “You can have a big space in a small house if you blur the inside and the outside – it gets you to interact with nature,” says Hellen. He brought the ground floor level down to the yard outside and the existing decking was taken up. This decking was to play a starring role in the house’s renewal – as the trellis itself.

“We love the idea that so much of our house has been re-used,” says Janelle. “We’ve managed to re-use a lot of the leftover material and are still using it, most recently for a small deck in the garden that catches the morning sun in the winter.”

With building materials close to hand, the project was moving swiftly until it arrived at what was to be the centrepiece of the extension, a stairwell suspended by steel cables. However, delays meant this was no longer an option. Hellen had another idea: “I knew another demolition job where some hardwood wall studs were earmarked for firewood. These studs held together a 110-year-old house so there’s a story to the stairs. We could have got standard stairs for $6000 to $7000 but by recycling timber we probably saved about $3000 to $4000 – and came up with an interesting feature.” The finished stairs – the project’s biggest challenge, according to Hellen – hang from the first floor, using the narrow wooden studs he recovered.

A bank of louvred windows on the north-east façade, behind the stairs and beside the polycarbonate sheet wall, allows natural light into the living space, with winter morning sun penetrating deep into the kitchen.

On the top floor, windows function as doors – with the trellis forming the guardrail – and the vines can be trimmed according to the privacy desired.

The windows, doors and sheeting enable sunshine and cooling breezes to pass through the building, keeping it warm in winter and cool and airy in summer. But the trellis and its vines are the innovative component in the home’s climate control. “Vines cover the south-west, west and north-west orientation,” says Hellen. “We haven’t painted the house; the plant becomes the paint, the colour and the texture.”

“It works beautifully,” agrees Janelle. “In summer the vines thicken. The breeze blows through them. In our bedroom, it’s like living in a forest. We haven’t calculated the savings on our energy bills but we didn’t find it super hot in the house last summer.”

The final part of the family’s brief was to gain a greater connection between the indoors and the garden. “The house now opens seamlessly onto the backyard,” says Hellen. “There’s a terrace with an outdoor fireplace and bench seat. You can watch TV inside while the kids play outside.”

The new plywood flooring is sourced from plantation species and approved by the Forest Stewardship Council; rather than being chemically treated, it was covered with a water-based polyurethane finish.

“Before we were in just one room. Now we have more living spaces, yet the house’s footprint has hardly changed,” says Janelle. “If you like a sterile, sparse environment, this isn’t your kind of house,” concludes Hellen. “It’s a living thing; that’s what you do in a house – live in it and out of it.”


Extract from Sanctuary: modern green homes magazine, issue 20, published by the Alternative Technology Association. See www.sanctuarymagazine.org.au.