A house made for life
The first strawbale house in its urban area, this flexibly designed and highly efficient Perth family home is adapting well as the needs of its occupants change.
This eye-catching house on a rise in the Perth suburb of Doubleview is unusual for several reasons, including the fact that it was the first strawbale house built in the Perth inner metropolitan area when it was completed eight years ago.
Owners Deepti and Christian Wetjen were looking for a small site close to public transport and local amenities when they spotted their oddly-shaped block in 2008. Despite its constrained building footprint, difficult access via a narrow laneway and location overlooking a busy road, the site presented opportunities to Deepti and Christian. A reserve to the north-east guaranteed access to northern sun, and being located at one of the highest points in the suburb, there were views to both the city and the Indian Ocean. Too difficult for many buyers, the block was also within their price range.
The couple, both architects, had mapped out some key objectives for their project: they wanted to build a compact house with a small footprint, to limit both their initial construction costs and loan interest payments over time. They also wanted a super-efficient building envelope so they could live without heating or cooling all year round, and they were keen to reduce their consumption of water and energy.
Because the site was larger than they’d initially sought and they regularly have their parents visit from India and Germany, the couple decided to create a two-storey home consisting of two self-contained units. They live upstairs with their kids, and the ground floor unit provides accommodation for visitors or for rental income. “Over the years it’s offered the possibility of increased community living, as well as financial sustainability,” says Deepti. “We have consistently sublet the downstairs unit, for a long time even renting it to friends with a young child, which was lovely. Sharing our house has forged many close friendships, and the income meant we could choose to work less while our own kids were small.” The design also offers flexibility as their children grow older and their needs change.
With identical floor plans for ease of construction, the units each contain two bedrooms, a bathroom, an open-plan living area and dedicated outdoor spaces. The upper level also features a loft-like multipurpose space in the roof, currently used as a sewing room, lounge, work and play space.
The wet areas are located in a square ‘tower’ built with aerated concrete blocks and clad in red metal offcuts, and the rest of the house is a laminated timber structure with steel bracing and rendered strawbale infill walls. Even though it was largely untested for urban housing in Perth at the time, Deepti and Christian were led to explore strawbale as it allowed them to build the house themselves as owner-builders – which they did, mainly on weekends and with the help of Christian’s cousin who was on site for several months. They were also drawn to the material’s very high insulative properties and the fact that it’s readily renewable, natural and an agricultural by-product.
A clever design inclusion is the moveable ‘wall’ comprising custom wardrobes that separates the two bedrooms in each unit. The backs of the wardrobes are fitted with acoustic insulation and wall panels, and because they are not fixed to the floor, walls or ceiling, they can be easily moved to change the size of the rooms. “When the kids were babies we had one in with us, so the other bedroom was smaller,” Deepti says. “But now they are sharing a room and sleeping in bunks, we’ve made their room bigger. At some point one of them will move out of that shared room and go upstairs, or downstairs, and we can just take the space back. It makes the plan very flexible as our needs change.”
The surrounding garden is equally well planned and flexible, with zones for various entertaining and practical functions that enable two families to share the outdoor spaces and still have some privacy. These include balconies and terraces, a lawn with swing and sandpit, a cubby house, garden shed, boat storage, fruit trees and edible gardens along the verge.
Below the driveway, tanks collect and store rainwater which is plumbed for use in the toilets. Another 3000-litre tank near the garden shed stores rainwater for irrigation and drinking. Greywater is treated onsite and used to water the garden, thereby reducing the volume of water flowing to the sewer. The two units share one laundry which is located downstairs: it’s accessible both from inside the lower unit and via an external door, so that Christian and Deepti can enter from the driveway when tenants or visitors are in residence.
A 2.3-kilowatt solar PV system generates more electricity than the two-family home uses over the course of a year, because there is no need for energy-intensive heating or cooling – just ceiling fans and the occasional use of a column heater on winter mornings. The rendered strawbale walls, insulated concrete slab and sandwich panel roof work together to maintain a comfortable, stable temperature all year round, and they also provide excellent acoustic insulation. Double-glazed tilt-and-turn windows sourced from Germany further reduce traffic noise from the adjacent busy road, and include integrated insect screens outside and blockout blinds inside.
Deepti sings the benefits of building with strawbale. “Perth sunshine in winter can be deceiving when we go outside and realise just how cold it is,” she says (and she’s wearing short sleeves on the June day when we meet). “There is something very cosy about living in a strawbale house. Yes, there is the thermal comfort and the stillness, but more than that, it’s the feeling of being in a sunlit cocoon.”
Even though they completed this project before their two children were born, Deepti and Christian set out to build themselves a house that would serve them for all the stages of their lives.
“It had to work for young kids, and then at some point when they leave it’s going to be just us. So we wanted a house that would be flexible enough to adapt to all these stages,” Deepti says. “We knew that we were going to be here for years, and we didn’t see the value in building a house purely as an investment. We just wanted a house that we would really love living in. And we do.”
The team at Melbourne-based design and build operation Positive Footprints has developed Carbon Zero Homes, a series of energy-efficient houses designed to generate enough electricity to offset the carbon footprint of their creation as well as their operation. Jeremy Spencer and Chi Lu tell the story.Read more