Prefab and modular building
Home Design May 22nd, 2009
House by Sparks Architects built with prefab units
In the last few years, both building materials and building labour have risen dramatically. Steel has gone up by 200%, transport costs have risen, and some plumbers, somehow, now cost almost the same as doctors! The expense of on-site labour and materials has been one of the main catalysts for the burgeoning of refabricated and modular building industry.
Off-site construction is considerably cheaper than on-site, and it minimizes the potential for disruptions to the building schedule; when trades do not turn up, or when the weather invariably turns foul. Any reduction in building time is a reduction in cost. The beautifully designed Mt Ninnery house (shown above) by Sparks Architects was built quickly and cost effectively by utilizing prefabricated units.
Quality control is also less of an issue with prefab building. Because the prefabrication is in factories, manufacturers are able to utilize tools unavailable to the site builder, such as custom manufactured jigs which ensure that all walls, floors and ceilings are square and plumb. Skilled craftspeople, under the watchful eye of the manufacturer construct each home to exact specifications. Like motor vehicle manufacturing, automated production lines and prefabrication reduce cost, produce more interesting material usage and greatly reduce wastage.
While prefab roof trusses and walls have been around for a while, prefab roofing and wall units are now appearing on the market and their use can considerably reduce building time. Riteck’s Prefab Roof Units are worth a look. Prefab (wall and ceiling) units come in standard sizes and if you build to multiples of their dimensions, there is less on-site, custom building and considerable savings are possible. However be aware of possible limitations for running services within these units.
Modular German Hauf Haus
One-step further is the fully modular house. They are built in room units, each one providing structural strength, insulation and both interior and exterior cladding. The wall and ceiling units have grooves for electrical wiring. However it’s only a matter of time before we see prefab flooring modules with options for pre-laid plumbing, and modules that are prewired. Houses like this are built in a few days.
Is this the way of future building? Probably!
In the US and Europe this type of housing is already quite advanced. There is even a prefab association in the US.
Modular German Hauf Haus Interior
Many modular housing construction companies there offer hundreds of options and design possibilities, floor plans and elevations, interior and exterior cladding, carpets, window styles, and choices of countertops and fixtures. Most fixtures, plumbing and electrical are in place before the modular home leaves the factory. Cost overruns are rarely occur. A basic unit can be purchased and further units added later.
Modular homes are built in about 1/3 the time needed to construct a site-built home. Some are faster. Living Homes, a modular home building in the US installed their first home on site in 8 hours (and documented it on video).
This type of building naturally radically reduces interest on construction financing.
Very cool NZ/Aust Bachkit modular home
It’s probably only time before the sophistication of the US and European module home industry is available in Australia. We already have a BRB’s fully modular light-weight houses but they have been used mainly in industrial situations. A more residential house is Gateway’s Prefab House. Another, in development, is the Quon Module House by Andrew Maynard.
If you can’t wait for these exciting developments, then perhaps you should a consider or a cool kit home by Bachkit.
With cheaper construction due to more off-site fabrication, and a drop in trade rates due to the depressed economy, building a house might even become less expensive. Or is that too much to ask?
Guest Blog by Writer and Copywriter Steve Connard
