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Designing for extremes
Prefabricated transportable houses—“dongas”—are experiencing a design revolution. Not only do they look different but also the new units now being offered on the market are built more substantially and use “eco-friendly” products. Inside a new donga the fittings can look as good as those found in an upmarket home.
Outside you will find such facings as 1.6mm steel “skins” that make sure it can withstand all the flying debris a cyclone is likely to fling at it. In part the market for the 21st Century donga is being driven by the more stringent demands of highly paid remote area miners. As one salesman explained: “These days high wages might get workers to a remote mine, but they will only stay there if the accommodation is good.”
Another factor driving the change is greater awareness of the risks presented by climate change and more extreme environmental conditions—particularly after Cyclone George hit the Pilbara. WA’s mining companies are now investing heavily in new dongas—both to replace the older types and ease the accommodation problems brought on by the resources boom.
there is also another factor in place that could see the new generation of dongas play a broader role.
In fact Rod Gibson, the New Zealand designer of the Habode “relocatable, recreational” house (illustrated above), sees his design as the possible forerunner of a new breed of emergency housing—the type of accommodation that could be quickly delivered to a disaster area after say an earthquake or cyclone had destroyed established homes.
The Habode and the company’s one and two-bedroomed range of “ihouz” units are all designed around the module of a standard international 40ft shipping container. That means they can be readily delivered through any port facility able to handle 40ft containers. Once on site, it takes no more than a few days to have the homes locked in place and fully functional.
The “ihouz” range costs about $60,000 and the three-to-four bedroomed Habode is around $140,000. (One measure of the difference between the new dongas and the old is weight. A traditional three to four bedroom donga weighs about 4.5 tonnes. The Habode weighs in at 12.5 tonnes.)
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Dual-use cyclone shelters
In response to Cyclone George, Perth firm Lowrie Construction has sped up development of its new CAT5 Cyclone Shelters. It uses a generic steel “super structure” in a range of buildings that can be “locked down” as required.
Emma Kallarn of Lowrie Construction says that the shelters had already been in development for around a year when Cyclone George hit the Pilbara. It was the cyclone that convinced the firm there would be a market for the product. The CAT5 Cyclone Shelters all utilise the super structure and are built to specifications above and beyond the BCA requirements. They are designed to be safe during the most severe cyclones (Category 5, Region D). And, importantly for coastal regions, the designs take into consideration that personnel may be using the shelters during post-cyclonic flooding.
The cyclone shelters can be designed for dual use, thereby avoiding the need for additional dedicated structures on site. Shelters can be kitted out for daily use as mess rooms, classrooms or dining/recreation rooms. Use of a shelter as a mess room would have the added benefit that food supplies would already be within the shelter during a lock-down.
The super structure consists of heavy I-beams welded into a base which, when set in concrete, reduces the risk of the building lifting due to a strong updraft. Walls are strongly reinforced, with beams at close intervals, and the use of a 3-layer cladding system (rather than the standard 2 layers) to prevent flying debris from penetrating the walls. Ms Kallarn says the fit-out can be tailored to the client’s needs, but standard “considerations” include everything necessary to sit out a 48-hour lockdown period, including a temporary power pack, communications hub, water tank, a basic medical room and a supply store. Features that may be incorporated include a reception area, seating area, entertainment area, air-conditioning and toilet facilities.
The shelters can accommodate up to 400 people, depending on the design. As the components are modular, a range of sizes and designs can be produced. Smaller shelters are designed to be relocatable on a truck or tilt tray, whereas larger shelters can be transported module by module. Assembly time is between 24 hours and 2 weeks, depending on size.
Search for innovation
Western Australia’s LandCorp is working with construction firms and building product suppliers to encourage innovation in designing housing suitable for the Pilbara. Last year it called for expressions of interest to identify builders and trades people interested in and capable of delivering residential housing in the region.
Part of the brief was to propose alternative building materials and construction methods. LandCorp’s Shravan Kashyap says that the shortage of builders and trades people in the region was a key motivator in the search for alternative approaches. Innovations identified as suitable included the Rapidwall system, a system of moulded wall panels employing glass-fibre-reinforced, water-resistant gypsum plaster.
It is said to be light, fast and economical to produce and assemble. Rapidwall panels are also resistant to cyclones if filled with sand or concrete after assembly. Another innovative firm identified was Vivendi Homes, headquartered on the Gold Coast. Vivendi has produced what it calls the VPS panel.
It consists of two outer steel faces with a polystyrene centre and can be used for both internal and external walls as well as ceiling panels. The company says VPS’ dense polystyrene centre makes for highly insulated and energy efficient houses. Complete panels are delivered to the site pre-cut.
This reduces construction time for a typical Vivendi house to around ten weeks, from site preparation to landscaping. The houses can be built to meet cyclonic standards. LandCorp is now using its 46-hectare site on the Nickol West estate in Karratha to demonstrate some of the innovative building options it has identified.
It is hoping that the display homes will generate increased public interest as well as attract more builders and trades people to the region. Innovative and sustainable housing, including homes using the Rapidwall system, are also being constructed at LandCorp’s Seville Grove site near Armadale.
Emergency housing
It is not only Rod Gibson who has been working on ideas for emergency disaster housing. (See Harbode above) The increased frequency and intensity of natural disasters is prompting a number of architects to come up with new ideas including some who advocate using the unlikely building material: cardboard.
Two designs for flatpack cardboard houses have already been developed locally. Australian architect Peter Ryan has been hard at work on his “cardboard house” concept for more than three years. A prototype was exhibited last year at the Canberra biennial.
The house is intended for use as low-cost emergency and disaster-relief housing, for eco-tourism and other short or medium term accommodation uses. The prototype was built with support from cardboard manufacturing firm Visy, with an eye to supplying emergency housing in the aftermath of Hurricane Katrina in the US.
The basic structure is made of cardboard and plywood, cladded with high-density cardboard on the exterior. With basic training, two people are said to be able to assemble it in less than a day. The price is $1500 per unit and because it’s almost entirely made of cardboard the Ryan house is almost 100% recyclable.
More cardboard
A more substantial cardboard house for “medium-term post-disaster accommodation”, has been designed by architects Peter Stutchbury and Richard Smith from Stutchbury and Pape, in collaboration with Sydney University’s Ian Buchan Fell Housing Research Centre.
Their cardboard house is designed as a flatpack for storage and transport purposes, and weighs around 2000kg, meaning that it can be transported by a light commercial vehicle.
They say it could be mass-produced for around $30,000 per unit. The house includes a number of features that would be useful in a post-disaster environment, including its own photovoltaic cells for power generation, built-in climate control, water storage and organic waste management systems.
Boxed solutions
Architects have also been experimenting with recycled shipping containers to provide robust and affordable emergency accommodation. Melbourne-based Sean Godsell’s “Future Shack” was first produced as a prototype in 2001.
The Future Shack is fully self-contained (including water tanks, solar power cells and a satellite receiver), and can assembled within 24 hours. It can be transported exactly like an unmodified shipping container, and costs around $30,000 per unit.
