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Archterra lead architect Paul O’Reilly had long dreamed of a client who shared his vision for a thoughtfully detailed, compact, energy-efficient home with clever passive solar design, all for the price of a project home.
But when that dream client failed to materialise, he decided to take matters into his own hands.
‘As I’ve got older, I’ve become hyper aware of the waste and excess that humans seem so attached to and felt a bit driven to express my thoughts on how to address this in a small way.’
In 2019, Paul purchased a parcel of land just a stone’s throw from the centre of Margaret River. The site, uniquely positioned between a landscaped reserve tracing the route of an old logging railway line and a protected bushland reserve, offered an enviable balance of proximity to both nature and amenities.
Today, the corner block is home to his sustainable-meets-accessible design vision, dubbed Sibling Houses: one is Paul’s own residence, and the other a testing ground for small-home design.
Built side by side, the two 98-square-metre dwellings share the same pared-back, boxy floor plan. Repeating the same footprint helped streamline the build, bringing the construction cost of each dwelling to $294,000 (pre-COVID price increases).
Their differences lie in the finer details, with variations in elevation and materiality giving each home its own distinct character.
‘Where it’s normal to just cookie-cut the same elevations, we’ve treated these differently in roof pitch and exterior materials selections,’ Paul says of the differences between the houses.
While House 1 is wrapped in galvanised custom orb (corrugated tin) — which reflects dancing blue, green and pink hues at different times of the day — House 2 features an organic mottled look thanks to its durable and cost-effective grey cement sheet cladding.
‘The flatness of the sheet is articulated with a spotted gum batten at the vertical joints and at random centres so that as the sun tracks across the sky the shadow formed at the battens grows and shrinks and makes the elevations appear dynamic,’ Paul explains.
Inside, the homes are predominantly painted plasterboard for cost efficiency, but each dwelling also features a unique material palette for warmth and texture: plywood ceilings in House 1, and rammed earth walls in House 2.
‘In terms of cost-driven compromises, I had initially wanted to have rammed earth in both houses but had to drop this back to just House 2, where it forms a fire-rated and acoustic wall on the boundary, so it’s performing a few roles and maximising my investment there,’ he says.
The property also sits alongside the Wadandi Track, creating opportunities for Paul to chat with passing locals about more sustainable ways of building.
While features such as LED lighting, heat-pump hot water systems and solar panels are, in his view, becoming standard practice, Paul believes a home’s greatest sustainability measure comes down to its size. For him, building smaller is one of the most meaningful ways to reduce a home’s environmental footprint.
‘I think we still miss the mark on the whole, with houses that are way too large for what we actually need,’ he explains.
‘If you can get your head around building a house that is half the size of what you think you need, then you’ve potentially saved half of those carbon-intensive resources from being mined, cut down, manufactured, transported and so on. I believe that’s where true sustainability starts to take shape nowadays.’
Paul is optimistic about the potential to make everyday homes more energy efficient without adding significantly to the cost of construction. While there’s no shortage of high-tech solutions promising better performance, he believes the fundamentals of good design are what make the biggest difference.
‘There is a lot of hype about technology to make your house energy efficient these days, and the reality is that correct solar orientation, thermal mass, insulation, glazing location and size, ventilation and appropriate shading are the key principles to address,’ he explains.
‘With those nailed, you’ll be fine, and there’s no reason for them to add any cost to the price of a house.’
