Environmentally sustainable house built

An environmentally sustainable home has recently been completed in Melbourne and has achieved a 6 Star energy rating from the Sustainable Energy Authority.

The key to the home, designed and built by Llewellyn Pritchard and his company Conscious Homes, is that it is claimed to put every known energy-saving product and concept to the test.

Pritchard says the house has a building life cycle of 100 years, which makes it cost competitive with most homes which are demolished before they achieve 50 years. Notwithstanding this, Pritchard estimates that the environmentally sustainable aspects added about $100,000 to his construction costs.

For instance, the home employs solar water heating and photovoltaic electricity generation with excess power returned to the grid. The home has also been sited to maximise energy efficiency by passive solar warming to achieve a consistent internal temperature of 20°C.

An 80,000 L concrete water tank has been constructed beneath the slab of the structure, actually underneath the carport, where the rain water run-off is conserved, ultraviolet treated to maximum quality and used in conjunction with a mains water supply. A Davey RainBank pressure system enables the tank water to be interactive with the mains supply in the event of mains power outages or low water stored in the tank. Constructing the rainwater tank underground also conserved space on the 715 m2 allotment. But it is judged on average rainfall statistics as having enough capacity to supply the year-round water needs of the house.

In addition, all household wastewater is clarified, treated and used to water indigenous garden beds and a no-dig vegetable garden via sub-soil drippers.

The building structure itself employs a hollow steel structural frame as steel was evaluated as offering the most resource-efficient hybrid structure with the lowest embodied energy.

The walls are double mud brick laid on edge with a separating core of Foilboard polystyrene foam for extra insulation. The mud bricks were made from the original excavations on site and provide thermal mass that moderates internal temperature with enough flexibility for removal if future extensions are contemplated.

Throughout the building, plantation pine is used in any framing with sustainably managed Vic Ash hardwood window frames which are double glazed with north facing openable highlight windows providing perfect crossflow ventilation.

Wherever you look, leading-edge environmental fittings are in use. For instance, low toxicity materials from local suppliers wherever possible are used throughout, including recyclable poly pipe for rainwater collection and waste plumbing while the interior wall colours were obtained using natural earth-based colour coats.

Before constructing his project, Mr Pritchard ensured that the original 60-year-old weatherboard house on the site was completely recycled including its timbers, bricks and concrete which were either reused or sold as demolition materials.

The Conscious Homes project is currently an entrant in the 2006 Green Building Awards.