Prefabrication in housing has a varied history in Australia and, while its market share remains small, innovative manufacturers are driving renewed interest. Production of high-quality energy-efficient homes, together with dramatically shaved build times, is a large part of its appeal.

According to Impresa House chief executive officer, Sean Morley, sophisticated machinery and integrated software technologies in off-site manufacturing is facilitating flexible building designs, rapid construction times and reduced material waste. This construction process is also helping to lessen occupational health and safety risks for workers, since fewer trades are required onsite during assembly.

All this without compromising on aesthetic and quality.

Impresa House is one of the panelised off-site manufacturers making strides in Australia’s burgeoning prefabrication industry. Through its state-of-the-art, 16,000-square metre factory, which opened in Derrimut, Melbourne in 2016, the business offers panelised solutions – walls, floor and roof cassettes – with a range of supported services for industry.

‘We can do design and construct, full turnkey projects, supply only or a mix of supply and install,’ Sean says. ‘A lot of what we do is work [directly] with builders to adapt a design to improve it wherever possible for efficiencies, both through the factory and assembly onsite.’

When it comes to residential and commercial builds, Sean says Impresa House has complete flexibility in what it can offer, from tiny houses to multilevel buildings. Its expanding portfolio is a good example to builders and consumers alike of what prefabrication does well.

In particular, the first turnkey house the company designed accomplished astonishing install and assemble times.

‘Everything was designed for the specific block of land, and we used design methodologies and guidelines to make it as efficient as possible,’ Sean says of the single-storey home in Tarneit, Melbourne.

‘This house had a large skillion roof, with a span of about seven metres, so we manufactured that as a series of roof cassettes in our factory, where we could then have the roof plumber come in and sheet it in the factory.

‘Once transported to site, we went from slab to lock up in two and a half days. Given that was in the first year of our operations we think we can shave a day off of that time now.’

While you take a moment to let that sink in, brush aside any assumptions the speed of construction skimps on quality. Sean says due to the company’s lean manufacturing system, focusing on optimising every step of the process, in addition to its quality assurance practices, the manufactured panels are extremely precise and fit together with millimetre accuracy.

‘Every single thing that we produce is checked before we ship it, ensuring you don’t have anything missing and it all fits together better onsite as well,’ he says. ‘There are well-known instances where things are missed onsite for whatever reason [but] here they’re fully checked. You immediately get a higher energy star rating and the building just performs better.’

Such accuracy and efficiency is made possible by computer-numerical-controlled (CNC) technology. The entire factory is set up with high-powered equipment from German multinational, WEINMANN, owned by HIA member, the HOMAG Group.

‘We’ve been extremely happy with the machinery, its efficiency and reliability. We haven’t had any issues since we started operating,’ Sean says. ‘We use SEMA software which drives our machinery, and it integrates quite well with WEINMANN machinery.’

Everything is adapted into a 3D design where all the connections can be seen: ‘you can basically overlay the architectuals with the engineering, and build in the layers that you’re going to manufacture.’

Every single panel is shop-drawn through the system and pushed out to manufacturing.

‘After it’s taken off the line and shipped to site, it’s a manual process of putting it together. [But] the full end-to-end process is extremely efficient and we’ve been very happy with the way it works. Our focus has been to improve our processes to take further advantage of what the machinery can offer.’

Through its current operations, Impresa House is capable of producing around 500-600 homes per year, depending on size and design, but Sean says the advantages are shown best when building volume.

‘If you’ve got a block of 10, this is where your real benefit comes in because you can go from slab to lock up so quickly,’ he says. ‘Then you can get all your other trades in, completing fit and finish.

‘Your build time is reduced dramatically right across the board, which means for builders and developers they’re getting their money turned over quicker…and for consumers they’re getting into their houses faster.’

The business is starting to see an increase in enquiries, not only from educated home buyers interested in the efficiency prefabrication has to offer, but also from industry. Compared to a few years ago, Sean says larger builders are taking a closer look at this production type.

‘We have more people approaching us about trialling and rolling something out in the years to come. It’s accelerating, and we think it’s going to continue to grow,’ he says.

This may be further boosted in academic quarters. The Melbourne University has taken an interest in prefabrication for the built environment and says it’s working to grow prefabrication’s market share within the construction industry from 5 to 15 per cent by 2025. This is to be supported by large-scale testing and training facilities at the university’s $1 billion campus expansion expected to be operational in the early 2020s.

Sean believes this may be achievable if it’s helped by other factors.

‘As building standards [improve] through regulation it will help the push towards prefabrication,’ he says. ‘Any kind of shift [regarding] financial challenges will assist…to make it easier to use off-site manufacturing.

‘It’s going to take coordination from a number of different areas, including education of students coming through learning about prefabrication, the different software types available and how it all works.’

Broader consumer education, with future homeowners being comfortable and confident with the idea of prefabrication, will also make an impact, he says.

‘The more people understand it and trial it, the faster that adoption is going to be.’