Building a house using traditional methods can result in waste and large environmental footprints, but a number of local building companies are rethinking how it’s done. Their different approaches, selection of materials and careful design can reduce a home’s ecological footprint during construction and over the life of the building.
Complete with kitchen sink
SALA Homes is a Brisbane-based company selling kit homes with an environmental emphasis. The houses begin with standard plans, typically smaller than the average new home. The plan is adjusted to ensure efficient passive-solar design exploiting prevailing breezes and to suit the buyer’s lifestyle.
“Our homes are the result of a balanced assessment of customer appeal, environmental impact, embodied energy, longevity and cost,” said Bruce Connell, General Manager at SALA.
“Choosing a sustainable house is an economic and environmental decision. People confuse cheap housing with affordable housing. An affordable house is low cost over its lifetime. Our homes feel spacious, and have a lower ecological footprint and lower running costs without compromising usability.”
SALA sources timber from sustainably managed, or plantation forests. Timber used for decking and external cladding is radially sawn to use up to 80 per cent of the log, compared with the traditional 40 per cent. House frames are steel or termite-resistant cypress pine.
Choices of cladding include timber, eco ply, Colorbond or hardboard. SALA decided on offering Colorbond cladding after weighing up its embodied energy – or the energy used to create it – against the need for maintenance, as well as its recyclability at the end of a house’s life. One criterion for selection of other materials was that they produce none of the volatile organic compounds (VOCs) linked with health concerns.
“It’s important to look at the lifetime of the house,” Mr Connell said. “People often make decisions about building a home based on one point in time, then suffer the consequences later of sub-optimal design or high-energy costs.”
Depending on the location of the new home site, SALA may source materials such as frames, flooring and kitchens from local suppliers, providing they are compatible with SALA’s ethos. “It not only reduces freight costs; sourcing local materials helps support the surrounding community, so there’s a social sustainability aspect too.”
A standard SALA home is complete with a solar power system, solar hot water, energy efficient lighting, and water and waste treatment systems and upholds the tenets of universal design. Universal design ensures a home is accessible to all people at all stages of life. This includes wider doorways, disability friendly appliances and easy access from outside.
“The designs are simple enough for owner builders to construct them. While there are other kit homes on the market, we don’t know of any that have our emphasis on sustainability,” said Mr Connell.
Fast, modular steel
“About 50 per cent of landfill is construction waste,” said Deb Grattan of Seacove Homes, “whereas we manufacture our homes in our Noosaville factory, minimising any waste at the building site.”
Seacove patented its modular construction system that uses lightweight steel. Each house is designed to suit the site and customer preferences, while ensuring passive-solar design for occupant comfort. Cladding materials include sustainable timbers and eco ply. Wall frames are guaranteed for 50 years.
A house can be delivered in three truckloads, including floors and windows. Modular construction means building is very fast – the home can reach lock-up stage within a week. Customers are responsible for fitting internal wallboards, kitchens and bathrooms, and energy and water systems.
The construction technique limits soil disturbance and is particularly suited to steep or awkward blocks. As each home is modular, it can be extended or demounted with relative ease.
“The construction is very strong as well as being fire and termite resistant. Because it’s recyclable it’s almost the ultimate sustainable home,” Ms Grattan said.
Steel and polyurethane panel houses
Maroochydore-based Ecohousing Building Systems use their own patented method to manufacture structural building panels made from lightweight cement sheeting with a polyurethane core.
Managing Director Tonny Bergqvist explains its advantages: “Polyurethane is widely used to insulate refrigerators, hot water systems, passenger jets etc. It’s inert, so it doesn’t give off VOCs (volatile organic compounds) and it has no interest for termites or vermin.”
Each building panel is load bearing and self bracing, so it is very strong without requiring a frame. They are also fire retardant and, importantly, very energy efficient.
“While insulation batts work on the principle of heat absorption, our panels work by heat exclusion. They have very low thermal conductivity, equal to about three metres of brick wall. Our buildings are five-star energy rated, but would be much higher if the scale allowed. Internal walls are fibre cement, sandwiching a polyurethane core. Because our houses are elevated with insulated floors, they maintain constant temperatures,” Mr Bergqvist said.
Ecohousing advises customers on home design and placement on the site to ensure passive design principles are followed. They provide doors and windows, but not kitchens, bathrooms or lighting. If required, they advise on water systems and will supply rainwater tanks and sewage-treatment systems.
The absence of framing means there are fewer components to transport to the site and construction can be undertaken either by the customer, or a builder. The panels can also be used in retrofitting and renovating existing homes.
“We’re not competing with either kit homes or fast-built project homes,” he said. “We are a unique part of the market.”
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I don’t see anything particularly outstanding in any of the photos available with this article. Too many windows, facing all over the place, foil facing inwards instead of out, even ridiculous statements like “insulation batts work on the principle of heat absorption”…… and where’s the thermal mass? People, you need REAL advice!
I have had first hand experience of steel studs conducting heat in western walls to such a degree you can run your hands along the wall and easily pick out every single one. I would not use it.
The loathing of concrete in this sector of the housing industry also has me baffled. To be sure it has a lot of embodied energy, but if properly/cleverly invested, it can completely negate the need for ANY heating and cooling, FOREVER! Our house has 150 tonnes of concrete in it, but it rates 6MJ/m2 and will NEVER need heating/cooling, and is so energy efficient it will repay every single MJ of embodied energy used in its construction in under 50 years. So in the long term, is is very sustainable, our house will actually achieve a ZERO footprint.. I guess that;s why we won a Glossy Award for it.
Your blog is interesting!
Keep up the good work!