Earthship: Sustainable building with 900 spare tyres

The three biggest banes of my existence are environmental guilt, having to live in a city, and bills. So when I heard about a three-day course that teaches novices how to build a carbon-neutral, self-sufficient “Earthship” home in the middle of rolling countryside, I packed my rucksack and headed off with all the eagerness of a prospector in a gold rush.

Earthships use recycled materials such as car tyres, wine bottles and cans to build a dwelling that provides its own heat, electricity, water and food. The first one was constructed in New Mexico in the seventies and the idea has gradually spread across the globe. Three have landed in Britain so far: two in Scotland, and one just outside Brighton, which was where sustainable living organisation the Brighton Permaculture Trust introduced me to their mysterious workings.

Day 1

The Brighton Earthship is built in the expansive grounds of 18th-century Stanmer House, which is where I first meet the group I am to share my three day eco-journey with. If I’m honest, I had expected a lot more beards, probably attached to retired academics with too much time on their hands, a generous pension, Green party membership and a box set of Grand Designs. But they are a lot more varied, and a lot younger, than that. There is an architecture student fed up with a lack of teaching about sustainability, a park ranger from Hampstead Heath, a QS turned conservationist and a Sicilian shamanist. To my relief, I feel only slightly under-pierced.

After a winding journey through a maze of allotments, we reach the Earthship. Curvy, earthy walls camouflage it against the landscape, yet the gleaming glazing on its south-facing side make it seem altogether more futuristic. It’s a Teletubby house, a hobbit hole and a UFO rolled into one. Inside, it’s more like the Eden project, with plant beds everywhere. There’s a circular office at one end, a thoroughly civilised bathroom, and an impressively large living room and kitchen. Although the whole thing is a bit light on soft furnishings – bare (low-energy) bulbs hang from the ceiling – I would live here in a shot. Now, how do I build one?

We start by learning how to do the rammed tyre walls, the most distinctive element of the Earthship’s design (see boxes). Recycled tyres are packed with earth, chalk or whatever material is to hand and these form the structure’s “bricks”. John, our seasoned US instructor, shows us how to ram the chalk into the tyres, using a sledgehammer to pack it in at an astonishing speed, pounding away like a human jackhammer.

We all have a go, and soon enough my repeated smashing of the loose stone causes the tyre to bulge.

It’s exhausting work, and my hands begin to blister as we work like a chain gang in the afternoon sun. John is asked if there are any tyre-packing songs. “It’s hard to sing when you’re out of breath,” he says, but shows no sign of flagging – unlike the rest of us. Each tyre can absorb up to four wheelbarrows of chalk and weighs about 300lb when finished, so the completion of a single one of them feels like a major project. But eventually my tyre is complete – immovable and solid enough to stub a giant’s toe.

The tyre wall, and the earth banks that buttress it, provide about 2m of thermal mass on the north side. During the summer, the sun heats it, and the mass stores the energy like a battery stores electricity. In winter, heat is released and in theory the Earthship stays tolerably warm. Rebecca Sarll, one of our course leaders, says the thermal mass is “quite protective, almost like a womb”. Yet indoor temperatures average out at 12ºC in winter. This can be raised using a woodchip stove, but as the group listens attentively to the presentation on thermal mass, our feet gradually turn to icicles on contact with the freezing flagstone floor. As we reach the end of our first day, I wonder whether my savings on gas bills might have to be ploughed back into fur-lined slippers.

Day 2

The next day we are set to work plastering a tyre wall with cob, a mixture of sand, clay and straw. The advantage of this kind of material, which looks and feels like muddy coleslaw, is that it is cheap and has a much lower environmental impact than cement. It can be used to coat indoor walls, although waterproof cement has to be used outside to protect the tyres. I struggle to create a flat finish and the end result is hardly something you could hang a picture on.

Muddy and tired, we take advantage of the Earthship’s rainwater collection system to have a tea break. Rain is channelled from the stainless steel roof into four huge tanks and is then passed through water filters and bacteria-zapping ultraviolet light. Not that the water emerges from the tap at anything more than a dribble, but it tastes a lot fresher than London’s. Water used in washing up and showering is filtered through tights to remove grease and goes to irrigate the plants.

Our tea has to be boiled on a gas hob, since the maximum power load the Earthship can provide is just over 1kW. “When you run the electric kettle, the whole system goes down,” says Rebecca. In theory, the Earthship’s prominently positioned wind turbine provides 900W of power at full tilt, but is temperamental and susceptible to turbulence from nearby structures. “It’s a bit of a joke, really,” says Mischa Hewitt, one of the builders of the Brighton project. Eighteen photovoltaic solar panels take up the slack, giving up to 6kW of power on sunny days.

During the winter, however, the solar panels might go for days without generating so much as a watt, meaning that the fridge will need an emergency diesel generator to carry on working. A costly array of batteries can store just over a week’s worth of electricity, but the Earthship couldn’t power all the appliances I use at home, let alone an energy-hungry family. Yet walking home through wooded paths at the end of my second day, I managed to convince myself that HDTV was something I could do without.

Day 3

If the first two days had inspired us, our final day brought us back down to earth – in not quite the way we had wanted. Kevan Trott, a chartered surveyor who has built his own Earthship in Normandy with his wife, Gillian, explained just how costly suitable land would be in the UK. A large enough plot with planning permission would set me back at least £100,000 in the south of England, and although I could do it for a lot less in the Outer Hebrides, I’d probably need to charter a jet if I ever wanted to leave.

Once the land is acquired, planning permission is the next hurdle, and was a problem in all the projects Kevan has been involved in. Brighton’s plans were originally turned down by the local planning officer because the area was one of outstanding natural beauty. Only after some “backroom lobbying” of councillors did the planning committee overturn the decision.

Kevan was able to get around these problems by building in France, where the land was far cheaper and the planning officers much more sympathetic. Even so, it still cost him €195,000 (£170,000) to complete. Just like any self-build project, costs can spiral, and the Brighton Earthship was no exception: the total outturn cost will be £330,000. Kevan says a friend of his who is doing his own Earthship project “doesn’t even look at his budgeting spreadsheet any more because it’s too painful”. Sadly, the expense of the project has been one of the reasons the Trotts have been forced to put their French Earthship up for sale for roughly the price it took to construct.

The tale makes our final lunch of olives, homemade bread and houmous a rather sober affair. Angelo from Sicily says the cost will prevent him constructing an Earthship in Italy for the time being. And for me, too, the cost is as prohibitive as I expected it would be. But Adrian, a carpenter with experience of renovating several houses, has a site, plans and a detailed budget for an Earthship near a beach in Cornwall.

And as I trundled back into London on an overcrowded bus, reflecting on the past few days, I was amazed at just how well the Earthship had lived up to its promises. It is almost completely self-sufficient, has little environmental impact, and providing you can hibernate through the chilly winter months, it would be perfectly tolerable to live in. Green construction isn’t for wimps or the hard up, but Earthships prove it is possible.