When we first visited New Zealand back in 1993, we had dinner with an acquaintance in a house that they’d built themselves from pre-fabricated sections. A two storey house that was really no different to every other house, apart from being arguably more robustly made, with a factory built frame, rather than one made by banging nails through bits of wood on site. On moving here we had the opportunity to stay in pre-fabricated Lockwood houses a couple of times. These seemed very impressive with their wood panelled interiors and certainly as unique as every other house, if not more so. Yet there seems to be a Kiwi prejudice against pre-fabricated houses, to the extent that some housing estates (e.g. Whitby nearby) have covenants forbidding pre-fabricated houses from being constructed. Doh!
Modern pre-fabricated houses can be uniquely designed from standard parts using computers. With tens of thousands of design permutations. An automated factory can then make those parts, which are transported to the site and assembled from generated instructions that ensure optimum construction efficiency. Walls can be highly insulated and sound proofed, with snap in and out features for electricity, telecommunications, and plumbing. No need to drill through wood and plaster to install those services. Houses can be assembled, quicker, more reliably and with fewer skilled specialists than ‘traditional’ methods. No leaks and quality problems due to human incompetence or poor selection of materials. So what’s the holdup?
Several it seems:
- Existing prejudice, as already indicated.
- Up-front cost of creating modern pre-fabrication factories.
- Vested interest in existing ‘traditional’ methods.
With regards time and cost saving, there remains the high cost and effort associated with:
- Land purchase and planning permission.
- Constructing foundations and getting services to the site.
Nevertheless, Kiwibuild (the current Labour/Greens Government’s abortive attempt to make houses affordable in New Zeland) could have funded factories to turn out low cost, high quality pre-fabricated houses. Availability of good looking, comfortable, low cost houses would quickly see prejudices disappear. Government could relatively easily revise resource management law, introducing measures to reduce the cost, effort and time needed to gain planning permission. No doubt there is also at least a partial solution to the cost and effort of constructing foundations and implementing building services if one looked hard enough.
There are now several off-site building construction facilities in New Zealand, however these are a long way from being automated factories. The largest one, in Auckland, owned by Fletchers, will shortly be able to turn out core parts for 2 houses a day, which doesn’t seem like much and is perhaps no surprise for a pretty underwhelming factory without robots.
In Sweden, which leads the world in building pre-fabricated housing, a new factory using the most up to date technology, being built by Lindbäcks Bygg, will be able to produce more than 25,000 square feet of turnkey housing per week.
The modular construction process has meant that Lindbäcks’ buildings are structured differently than conventional timber developments. Modules have to be sturdy enough to ship and minimise redundancy in floors and ceilings. The need for strong, solid exterior walls in the modules means that floors are hung from the walls, as opposed to having walls stand on top of every floor.
To achieve a successful ‘Kiwibuild’, the Government could have emulated Lindbäcks’ factories in this country, either inviting the company to setup here or by paying for their expertise.
The reality though I suppose is that we don’t have a Government, or 
government, with the vision and capability to progress anything significantly different from what already exists, let alone challenging an entrenched construction industry to architect such a major, evolutionary advance. To achieve that in NZ, we’d probably first need to get rid of progress killing MMP.