Is prefab the answer to pricey Passive House builds?
Poppy Johnston | 26 May 2020
It takes precision and care to construct an airtight building that’s good enough to pass the tough blower door test for Passive House certification. None of it is cheap. But what if you could keep costs down by prefabricating most of these ultra-comfortable, low energy buildings? That’s exactly what Darryn Parkinson had in mind when he set up a manufacturing facility in Western Sydney.
Passive House is starting to gain ground in Australia but typically, it’s not exactly an inexpensive option.
While the high-performance windows, doors and other specialised componentry are now easier to bring to Australia, this specialised method of construction relies on extreme precision to ensure the building envelope is airtight. That means it’s supervision-heavy – with demand for builders inexperienced in the method – and therefore costly.
悦博体育赌场Parkinson wanted to be able to construct Passive House buildings affordably. He looked to places such as Europe and the US, where Passive House is better established, and found that panelised components erected onsite worked well to guarantee precision without costing a fortune.
悦博体育赌场Under the business name Eclipse Passive House, he’s now setting up a manufacturing facility in Western Sydney to make prefabricated Passive House element, making him among the first in Australia to do so. Melbourne-based Habitech Systems is another.
悦博体育赌场Once in full swing, Parkinson imagines employing around six people work in the facility and another six to eight to work as construction crew.
The aim is to be able to remove the cost premium of building a Passive House using traditional methods. Realistically, the homes will still be a premium product, he says, but the hope is that they will cost no more than a well-designed architectural house.
The troubling state of offsite construction in Australia
悦博体育赌场Parkinson is well aware of the risk of starting a new prefab business in Australia. A few wobbles have been felt by the fledgling industry over the past few years, including prefab and lightweight timber pioneers Strongbuild going into administration after losing a major contract in 2018.
While the model “hasn’t had a good track record of success”, Parkinson hopes to avoid becoming another early stage industry victim by treating Passive House as the product, and prefabrication as the best method of delivering it.
“Prefab is the methodology to do Passive House. It’s the best way because you can manage it better when building offsite, including the quality of tradesman. You can assure cost control.”
While recognising that it’s still early days and that we’re just coming out of a pandemic lockdown, Parkinson’s instinct is that serving a niche market such as Passive House is lower risk compared with some businesses that positioned themselves with “prefab first”.
Another departure from the typical offsite construction model is that the business will employ tradespeople to both construct the panels and assemble the buildings – a complete Passive House solution. This will minimise the risk of not passing the stringent blower test for Passive House certification.
悦博体育赌场Parkinson has been very conservative in the initial investment outlay, with the 12,000 square metre manufacturing facility capable of producing around 20 dwellings a year.
悦博体育赌场“We’ve spent of time researching the right solution and the right amount of money to deliver it.”
Not restricting architects is important
Along with the business model, a lot of thought has gone into the product itself. Critically, the prefabricated product allows for design freedom.
“The aim all along has been for a system that doesn’t push back on architecture or design too much.”
悦博体育赌场Parkinson is a fan of larger panels that might need bigger trucks but that keep construction time down. While not suitable for all sites, Parkinson says it’s generally better to build quickly over a couple of days using a crane rather than trucking in many smaller modules and taking longer.
Small single storey homes to start, but hopefully multistorey buildings one day
悦博体育赌场Parkinson says there’s work in the pipeline for the business, starting off with single and two storey residential units. In the future, he hopes to develop a system that can go up multiple storeys as in Europe.
悦博体育赌场He’s currently keen to perfect the various techniques at the premium level because the lessons will trickle down into the volume market and eventually Passive Houses will no longer be a niche product.
“We believe strongly in what Passive House delivers as a system of building.
“There’s so much building science behind a Passive House.”