When people think of undertaking an environmentally friendly renovation on their homes, the first thing they might think of is replacing old inefficient appliances or going electric.
But for an increasing number of ecologically minded homeowners, reducing construction waste and recycling or repurposing existing infrastructure is just as important and even more affordable.
Minimum change for maximum benefit
Andrew Sweatman and his wife are empty-nesters approaching retirement who live in a century-old Edwardian house in Melbourne’s inner north. The couple’s renovation should ultimately lift their home’s energy rating from 0.9 to 7.7 stars.
But rather than following the trend of ripping the guts out of the house, they have elected to keep as much of the original building as possible intact and recycle the good parts, including elements of the back yard.
“This was a key philosophy of our architects too – we kept the same footprint with no massive rebuilds,” says Sweatman. “We realised it was time to freshen things up for our retirement and fix some key problems to improve the environmental performance of the house so this would be our forever home.”
The couple started by identifying the features they wanted to keep including the flooring, framing materials and some plasterworks and renovate around them, minimising costs and recycling where possible. They also maintained some original features like the front door and stained-glass windows.
“We wanted to maintain heritage aspects of the house instead of simply demolishing the whole home and keeping just a facade. We also decided we didn’t want to destroy the back yard to extend the home to be a mega house.”
The Sweatmans are improving the homes energy efficiency by installing solar, batteries, and more efficient electric appliances. They are also installing insulation under the floor, in the walls and the roof, triple glazed windows and designing upgrades to maximising passive solar exposure.
In this way they share architect Brave New Eco’s operating mantra of “minimum change for maximum benefit” in their approach to the project. “If you can minimise waste in this process it’s an extra benefit, you can do lots of amazing things with an existing building, you don’t need to demolish to get beauty just because home shows or designers tell you that it’s not possible,” Sweatman says.
Embracing ‘circularity’ as a renovating principle
Linden Thorley, a Sydney-based architect and chair of the Australian Passivhaus Association Retrofit Committee, says one of his top considerations is determining how much of a building can be kept intact in order to minimise construction waste, a principle called “circularity”.
He says in some cases the costs and risks associated with taking buildings apart, storing the materials and finding new uses for them can be costly, but there are huge benefits in reusing parts of the existing building.
“Many existing homes can be significantly improved to make them more comfortable and healthier to live in without completely demolishing them.”
Thorley says he often renovates houses through incremental improvements rather than a complete rebuild, staggering work to target low-hanging fruit in a home and focusing on the potential for passive solar are key elements to consider. “There’s no point adding heaps of insulation if there is a draft blowing through it. We can test for improvements in air tightness before spending money on additional insulation that is harder or more expensive to install.”
Maximising the use of available sunlight to warm the home in winter and exclude heat via well-placed shading is also a key consideration. “To support this we need a really well insulated, and relatively airtight building envelope that allows us to maintain our preferred inside temperature. This includes really well sealed windows when they are closed and excellent ventilation.”
“Learning to reuse materials instead of always using new ones is something we have to learn to do in a finite world,” he says.
