From prefab to ab-fab

22:36, Apr 13 2013
Fab 1
Wellington architect Chris Moller has designed a click-raft building, in which plywood pieces can be clicked into place like Lego.
Fab 2
This modular, high-density Anne Salmond house can be put together in a matter of weeks.
Fab 3
The "fridge house" costs $100,000 and needs only one heater to warm all of it in winter.
Fab 4
The exterior of a two-bedroom bach by Studio 19, a group of Unitec architecture students who work with architect Dave Strachan.
Fab 5
The interior of a two-bedroom bach by Studio 19, a group of Unitec architecture students who work with architect Dave Strachan.

The once-tawdry prefab has transformed into the architecture of the future, writes Sarah Catherall.

For most of us, the word prefab conjures up images of draughty, nondescript boxes that have served as temporary classrooms over the years. But a new generation of prefab houses and baches now sit on sections from one end of the country to the other.

The prefab - a building that is built or partly built in a factory and shifted either whole or in parts to a site - also forms a big part of our architectural history.

The first New Zealand prefab house was the Treaty House in Waitangi, built in 1833, and early immigrants were encouraged to bring the framework for their cottages with them in the 1800s. About 1600 railway cottages were built as kitsets in a Frankton factory between 1880 and 1929 for North Island railway workers and their families, with each one taking about two weeks to put together on-site.

Since the mid-50s, companies such as A1 Homes, Lockwood and Keith Hay Homes have been providing kitset and prefabricated homes, but now smaller architectural practices too are increasingly choosing factory-based building over the traditional mode of constructing everything on site.

And the authors of a book about prefabricated houses, and the architects who are designing them, say we should get used to it, because residential homes will increasingly be designed on computers and mass-produced in factories.


"Prefab is absolutely the future of the building industry," says Mark Southcombe, a Victoria University senior architecture lecturer and co-author of Kiwi Prefab: Cottage to Cutting Edge. "There's a huge amount going on in the prefab sector, and suddenly we've got this fantastic hotbed of innovation."

Apart from the array of local architects and companies designing and building prefab homes, baches, and buildings, Southcombe points to Austria and California, where prefabrication is now the preferred mode of building and no longer associated with poor, cheap design.

"In California, prefab is now associated with the top end of the market, because the quality is so much better, as it's all made in a controlled environment. In New Zealand, we have a lot of raw timber, and we have the potential to become a prefab hub for the Pacific Rim."

The benefits of building parts in a factory and assembling the building on site are many, says Southcombe - cheaper and more cost- effective, quicker from start to finish, more environmentally friendly, and less affected by issues such as bad weather.

Southcombe has designed a "jigsaw house" made out of cross-laminated timber, which resembles plywood as thick as a wall. Immensely strong, he says it can be put together on site in a day. He's hoping to build a prototype in the next two years, as part of a university-backed project.

Chris Moller, of Wellington, has designed a click-raft building, again with factory- built plywood pieces that can be literally clicked into place like Lego, the design and layout responsive to home owners' needs. With a kindergarten for Christchurch in production and several houses on the drawing board, he hopes the end cost will be less than $2000 a square metre (compared with about $3000 a for a non-prefab home).

"My ambition has always been to produce something of radically better quality, much faster and cheaper," says Moller. "The time is right for radical low-impact houses, for super inexpensive, accessible places we can live and work in that are in tune with our fragile planet."

Andre Hodgskin kicked the prefab craze off with the stylish bach-kit he designed in 2000, and he has since followed it up with the "ipad" that costs $125,000 for a two-bedroom place with click-on decks. Nelson's Irving Smith Jack Architects has built a "fridge house" out of refrigeration panels usually used in warehouses or coolstores. Costing $100,000, it is so well-insulated that one heater can warm the whole house in winter.

Architecture students are also involved in prefab projects. At Victoria University, four students designed the environmentally friendly First Light house, which was assembled on-site for an eco-design competition in Washington DC in 2011, before being packed up, shipped home and sold off.

For the past six years, a group of Unitec architecture students has worked annually with Auckland architect Dave Strachan to design a two-bedroom prefab bach. Called Studio 19, the student designers have completed six such baches, building them either at Unitec or nearby, and then trucking them to each site.

Strachan says the advantages are huge. "One of the big things is that all the resources are handy, such as the tradespeople. You've got better control over the conditions because everything is built under a covered area or in a workshop. It's quicker, and you're not waiting for a plumber to show and he doesn't turn up because he got too busy that day."

His firm, SGA, is also embracing the prefab model, designing homes that are more efficient, warmer, drier and exceed building codes. Particularly suitable for areas that need high to medium- density housing, he is creating a prefab apartment building in Auckland that will, literally, be slotted into place after the walls and other parts are built offsite.

"The only way to deliver the volumes of buildings that we need in places like Auckland and Christchurch to a high standard is to use factory standards. You can save weeks if not months in time."

Wanaka architect Anne Salmond has designed several modular, high-density homes around Queenstown, a series of prefabricated pavilions responsive to their sites and clients.

She also has one at Christchurch's Home Innovation Village. Built in an aircraft hanger at Wigan, it was shifted there at 3am one morning. "It was basically put straight on to the foundations," she says.

Of benefit to Christchurch quake victims, she says the whole construction process could take six to eight weeks rather than six to eight months - her design takes a month to six weeks to be built.

However, at the top end of the market, Salmond expects larger bespoke houses with bigger budgets to continue to be built on site. "We're designing a house with a concrete roof and that obviously couldn't be a prefab. However, I do think people will start to think prefab rather than assuming a house will be built in the traditional manner. It's broadened the options of how we can build."

Pamela Bell, chief executive of the newly formed Prefab New Zealand, says: "Prefab is going to be increasingly relevant as we try to solve some of the housing shortages around Auckland and Christchurch. We can't deliver the homes that are needed. Most builders are a one-man band, and they'll build one house in a year."

There are challenges for the architecture community, though. As Southcombe puts it: "Architects are typically quite sceptical and cautious about the idea of them repeating a design. But the really important point to make is that it's very co-operative and cross- disciplined. You get architects, builders and manufacturers all working together as a team, not as three teams."

The Dominion Post