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Earthship Ironbank

ironbank
Zoe and Martin Freney outside the entrance. Photo by Koren Helbig

Nestled among gums in South Australia’s Adelaide Hills lies an elegant home, made largely of rubbish – old car tyres, glass bottles and recycled cans. Such unconventional materials are key to constructing an Earthship, the now global ‘radically sustainable’ building technique pioneered by renegade American eco architect Michael Reynolds since the 1970s.

It was a visit to Adelaide by Michael himself that sparked this project at Ironbank, one of the first official Earthships to be built in Australia. Michael had popped by to speak at UniSA in 2009 at the behest of Martin (Marty) Freney, an industrial design lecturer there. Afterwards, the pair headed up to Ironbank with a few students for a hands-on lesson in creating the Earthship’s fundamental building block; tyres ram-packed full of soil, which they casually arranged into a U-shaped wall. In the years that followed, Marty gradually realised he had the makings of his own small Earthship and after gaining council approval he launched the project in earnest.

An official Earthship must meet six design principles:

  • produce its own energy
  • produce its own water
  • treat its own wastewater
  • use only passive heating and cooling
  • be constructed from sustainable and recycled materials
  • produce its own food

‘It’s called an Earthship because it’s like a boat on the ocean that has to do everything for itself,’ Marty says. He estimates ticking all those boxes cost about $170,000, though he saved truckloads on labour as volunteers came from around the world to learn while lending a hand with construction.

Constructed Using Society’s Waste

All up, about 1000 old car tyres, pounded full of soil, went into this Earthship’s walls and neighbouring rainwater tank. ‘Tyres are all over the planet – anywhere you find people, you pretty much find tyres,’ Marty says. ‘I actually get a real blast out of going to the tyre store and picking up old tyres.’ In a similar attempt to reuse something too often sent to landfill, the internal walls are dotted with the muted greens, whites and browns of glass bottles, necks cut off and two bottles taped together to create a kind of circular brick.

Loads of old bottles and recycled cans went into the bathroom too, all covered with cement and mortar. That was polished to a waterproof shine using tadelakt, an ancient Moroccan lime plaster that Marty and his volunteers painstakingly burnished by hand, rubbing the surface with rose quartz stones. In the Earthship’s main living area, floors were made from sand and straw, mixed to make a hard earthen floor then sealed with linseed oil.

Natural Heating And Cooling

Earthship Ironbank’s main living area, which serves as a combined bedroom, kitchen and living room (other Earthships have three bedrooms or more), is dug into the hillside and covered over with soil. The earth creates a kind of thermal wrap that keeps the room warm in winter, helped out by a fireplace that doubles as an oven and stove, and remarkably cool even on the hottest of Adelaide’s fierce summer days.

The home is flooded with natural light thanks to huge floorto- ceiling double-glazed windows that act as a powerless heating and cooling system. North-facing, the enormous windows soak up the low-hanging winter sun and work as a natural heater, while eaves block the baking heat of the summer sun. ‘It’s performing quite well here in the summer. If it’s 40°C outside, it’s 25°C in here,’ Marty says.

But the most crucial component of this overall system is mostly hidden from view. Dug about two metres beneath the Earthship are two large ‘earth tubes’ that pop up in the main living area, through a grille cut into a bench chair. When the glass living room doors are closed but the skylights above them are open, hot air rises up and out of the room, drawing cool air in from below. ‘It’s a totally passive system, just working with the physics of hot air rising and the coolness of the earth,’ Marty says. ‘If you close the windows, the temperature in the living room will jump up within half an hour or so. It’s like shutting a car on a hot sunny day, and that’s your heating in winter.’

ironbank
ironbank

ironbank

Clockwise from above: Designed and drafted by Marty Freeney in consultation with Mike Reynolds; The bathroom with tadelakt bath; Earthship Ironbank from the north; The internal greenhouse. Photos by Koren Helbig

ironbank

Collecting Power From The Sun

Rooftop solar panels hooked up to a converter power the entire house, including the hot water system, backed up by 12 batteries. ‘With an Earthship, you become the power and water company,’ Marty says. ‘I probably need to put away about $1000 a year for when the batteries or converters need replacing, but I still think economically it’s much better than paying three or four times that to the electricity and water utility companies.’

The system is easier on the environment, too, says Marty, who researched Earthships’ thermal performance and environmental impact for his doctoral thesis. ‘Even though there’s lead in those batteries, it’s actually highly recyclable. The alternative is gas fracking and coal mining, poles and wires everywhere. It’s the same with the water utilities. A huge amount of resources go into pumping water, chlorinating water, maintaining dams and draining the Murray River. Just having some rainwater tanks, catching water off your roof and having a pump with some filters is a whole lot better, environmentally speaking.’

Harvesting And Reusing Rainwater

Atop the Earthship’s main room is a large, gravel-covered U-shaped roof that acts as a giant water collection basin. The roof funnels water to two 5000-litre poly tanks buried behind the Earthship, which supply the house. Any extra runoff is channelled into an enormous 45,000 litre tank made from 300 soil-packed tyres. Incredibly, that’s pretty much all reserved for bushfire fighting purposes, though the tank is twice the council-mandated minimum for the fire-prone Adelaide Hills area.

With such a huge body of water essentially waiting in backup, Marty’s found a way to put it to good use in the meantime – as a swimming pool. ‘It’s beautiful and cool during summer when you jump in to swim, because it’s essentially buried in the cool, stable temperature of the earth,’ he says.

Supplying the hot water tank is a third 5000 litre poly tank plonked further up the hill, which can operate via gravity feed but gets a helping hand from a bushfire-safe electric pump. Each tank feeds into the Earthship via a ‘water organisation module’ (WOM), which allows Marty to pump water from wherever he chooses at the flick of a valve. A dirt sediment filter and chemical removal filter inside the WOM also ensure rainwater is safe for drinking.

Marty keeps an eye on his water use via a series of exposed plastic pipes in the bathroom, which contain orange floats that rise or fall depending on each tank’s water level. ‘It’s essentially like the fuel gauge in your car, which tells you how far you can go,’ Marty explains. ‘So that in summer, if you know you have a bit of drought situation, you can see how much water you have in your tank and use less water if you need to. These gauges are a really important part of telling people how to change their behaviour.’

Containing And Treating Greywater

A key feature of Earthship design is the ability to recycle wastewater, making the house self-sufficient with only 250 mm of rainfall a year – about half of what Adelaide receives. ‘Earthships in the USA are totally self-sufficient in water mainly because they reuse and recycle the water four times: first for the bath, washing machine and hand basin; second for irrigating an indoor food garden; third for toilet flushing; and fourth for irrigating an outdoor garden,’ Marty says.

Unfortunately, SA’s health officials wouldn’t play ball, ruling the reuse of greywater in the Earthship greenhouse beyond the scope of wastewater codes. That system would have sent bath and shower water direct to the plants’ root system via a gravel wicking bed laid beneath the greenhouse garden. ‘The soil and the roots actually take out a lot of the pathogens and bacteria. It acts as a bio filter,’ Marty explains. Instead, he’s now forced to send water to a conventional septic tank and then out into an area that will soon become a fruit orchard. But he’s hopeful South Australia will evolve to allow greywater recycling in the future.

Growing Food Inside And Out

Perhaps the most visually striking Earthship element is the long and narrow greenhouse stretching across the front of the building. Ostensibly a corridor entry to all rooms, it doubles as a productive garden bed for edible plants such as bananas, tomatoes, ruby chard and chillies. ‘Part of the deal is managing this garden so that in the winter you’re letting the sun in and in the summer you’re blocking the sun out,’ Marty says. Outside is productive too, with herbs growing in tyre planters and a huge summer pumpkin patch covering both sides of the house, yielding mountains of produce.

A Constant Work In Progress

Since late last year, the Earthship Ironbank has been open as a bed and breakfast, partly because that was the easiest way to get building approval with another house already on the block. But Marty, who has now launched Earthship Eco Homes and is consulting on five new projects, admits he’s still tinkering around the edges of his own design. ‘I don’t know if it will ever be finished. We’re building an outdoor bath and some little steps…the whole front area will hopefully be nicely landscaped and we will have terraced gardens,’ he says.

Marty hopes throwing the doors open to visitors will encourage more people to consider self-sufficient living. ‘This is a really powerful idea, that you can live off the grid without needing the government to supply all these life essentials. It takes a whole lot of stress out of your life when you don’t have bills to pay.’

Earthship Ironbank is available for rent: www.airbnb.com.au/rooms/1611697.

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