Hayball director David Tweedie talks about how prefabrication and the increasing encroachment of technology is changing the way architects design and build in an environment where sustainability is a major focus.

How is the design process impacted when it comes to designing (and eventually building) with prefabricated and/modular components?

Design time is a major factor, with off-site construction and installation leaving no real opportunity for adjusting and adapting on-site. We are really designing carefully to a high level of resolution in order to minimise time on site.

For example, our Caulfield Grammar Learning Centre was installed in an unprecedented single day. As you can imagine, locking down design details earlier in the process is therefore key – whilst still retaining the broader vision and experience to identify and accommodate the unexpected. In essence, we have to design the puzzle as opposed to putting the puzzle together bit by bit.

Is this type of building method becoming more popular, and will it ever totally replace the traditional way of building?

Prefab is definitely on an upward growth curve, and I think looking back, we’ll see a spike in the current era. It may be important to note that this methodology has actually been around for years, but the dynamics of labour costs and the deployment of higher technologies are currently making the equation work.

With prefab, you have to commit early and invest time and energy (rather than progressively resolving the building with the design team and ultimately the contractor). So, hindrances remain, particularly when it comes to financing and procurement risks.

But the global market has naturally progressed, and our local sector is changing, driven by basic economics of speed and therefore cost savings, and potentially quality control. As the dials of regulation and sustainability are repeatedly set a little higher, I really do see prefab becoming the principal construction method for some typologies.

It’s arguably most popular for residential buildings, with some components, like façade work, increasingly prefab by default. Our large-scale residential portfolio – including projects such as the La Trobe Street Student Accommodation in Melbourne – increasingly involves a substantial component of prefabricated manufacture and assembly off-site.

This project is a pioneering one: at nearly 150m high it will be one of the world’s tallest prefabricated student accommodation buildings. Fully designed for manufacture and assembly offsite, the construction technology dramatically reduces both construction time and on-site impact during installation.

Is there a cost-saving to this type of building method and if so, what on average would it be?

Extended design time equates to time saved on site – potentially realising cost savings of between 15 and 20 percent. Prefabricated buildings ultimately demand less time of a builder (the biggest expense of a development) and significantly reduce the overall construction period of a project.

Also, because we’re working in a controlled environment, materials can be standardised, and cost waste reduced. Productivity is also exponential when construction professionals can work without risk of inclement weather and safety concerns on building sites, mitigating unexpected delays and damages.

However, the Australian prefab sector is still in its relative infancy, and it may take some time for these cost savings to become drastic differentiators. Currently, we have limited choice of tenderers, inflation is a risk, and there is simply more demand than supply. But the overall trend of favouring this methodology is sure to lower costs in time to come.

The use of cross-laminated timbers and glulam is gaining some traction in the multi-res and commercial build sectors. Would you say that this type of prefabrication will become a lot more common in the future, and if so, why?

With Hayball being part of the Australian integration of Cross Laminated Timber (CLT) since 2013, there is no doubt in my mind that prefab materials like CLT and glulam will become core parts of design here in years to come –having already influenced the residential market in Europe in recent decades. Part of what makes CLT so innovative is its low environmental impact, direct savings, faster delivery, ease of transport and installation, and reduced foundations/infrastructure.

The Library at The Dock was the first public CLT building in Australia, with its CLT components being built in Austria, shipped over and screwed together onsite.

The build boasted unparalleled speed, ease and affordability. It’s not only construction benefits that were realised – the interior ambiance of the project is improved in a qualitative sense. For all these reasons, we also rigorously investigated use of the technology to full design and documentation of a major multi-residential project called Studio Nine, Central Precinct – a 220 dwelling project in Richmond, Melbourne.

Branko Miletic

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