Project home to Passive House

Sarah and Shane’s initially modest home refresh project was upgraded to a full Passive House retrofit, with stellar results.

It’s a sad reality that for various reasons, many initially ambitious build and renovation projects have their energy efficiency features stripped out and their sustainability goals downgraded along the way. Not so with Sarah and Shane’s renovation in Williamstown, bayside Melbourne, though. In fact, they went the other way: after discussions with their builder, their initially modest internal refresh was upgraded to a certified EnerPHit project – the Passive House standard for retrofits.

The couple learned about Passive House while planning a small footprint, off-grid sustainable house for a block of land they owned an hour or so north-west of the city. When their second child was on the way, however, they changed their focus and began looking for a house closer to family that would work as a home base for the kids’ school years. After an 18-month search, they settled on a 1994 brick veneer project home in an estate built on an old military training ground just a stone’s throw from the beach and close to where Sarah grew up.

“Though it was only 25 or so years old, the house was pretty dispiriting, with lots of small boxy spaces – it really needed an upgrade,” Sarah remembers. It was also leaky and badly insulated. The dated chandelier and velvet drapes in the lounge were quick to go, and Shane and Sarah had their sights set on a kitchen and bathroom update: just a modest project. However, when their builder Matt Carland investigated further, it was clear that a more major internal retrofit was indicated. “Our initial airtightness testing came back at a whopping 35 air changes per hour,” he says. “The house really needed to be stripped back to the studs to be insulated and made airtight, and given new, better-performing windows.”

Luckily, Sarah and Shane were able to stretch their budget for the more extensive project, and when Matt suggested they run the numbers and see whether they could achieve EnerPHit certification, they were enthusiastic. “In the end, it was only going to take small extra interventions to get there, and going the whole hog for EnerPHit came in at about the same cost as not going for it,” says Matt.

The bones of the house were good, and the family didn’t need any extra space; at 183 square metres it was already palatial compared with the compact Docklands apartment they were moving from. So Matt and interior designer Erin Fairmaid of HèHè Design came up with a plan that involved retaining the brick walls, stud frame and roof, and making only small internal layout changes. The opening between hallway and lounge was made bigger, and a wasteful dogleg entry to the main bedroom rejigged. The laundry was enlarged to accommodate the mechanical ventilation system, and a pantry was added to make better use of the area in the centre of the house. The kitchen/dining/living space at the back of the house was opened up for better flow.

Once stripped back internally, the house was insulated and a vapour-permeable membrane added for airtightness. All windows were upgraded to uPVC-framed triple glazing, their installation carefully detailed to make sure they didn’t cause moisture issues. “For us, the scariest part of the project was moisture management,” Matt says. “Being so close to the beach, the house has to withstand wind and driving rain, and we were worried about moisture transfer through the exterior brick as we couldn’t install an external membrane. We opted for polyester insulation because it’s hydrophobic.”

The finished house is light, bright, quiet and warm, with timber detailing using Crafted Hardwoods products in key places [Ed note: see Products in this issue for more on this new offering]. “We did make some sacrifices, like avoiding expensive custom joinery, so we could spend the money on efficiency measures instead,” says Sarah. “For example, we went for IKEA shelving for the walk-in robe as it was a fraction of the cost of getting it custom-made.”

One disappointment is the innovative cork flooring product selected for its promised insulative value and sustainability credentials; sadly it turned out not to be fit for purpose and needs rectification. The couple are philosophical about it: “We were guinea pigs for a lot of things, some that worked really well and some not so much,” says Shane.

Overall, though, Shane and Sarah are very much enjoying their new home, which passed its tests for EnerPHit certification. “We loved the process of working with Erin, Matt and Passive House consultant Cameron Munro, solving problems and choosing materials, and setting things up for our family for the long term,” says Shane.

Sarah mentions that her favourite thing is how comfortable the home now is. “Sometimes we have trouble convincing the kids to put jackets on before we go outside in winter,” she laughs. “It’s a good problem to have.”