The ultimate in green building design, Earthships are zero waste, self-sufficient homes constructed using recycled and natural materials. As power prices and construction costs increase, these natural buildings are gaining wide-spread attention as an affordable housing alternative. Adelle King reports.

In February, Prime Minister Malcolm Turnbull told delegates at a conference hosted by The Australian Financial Review that Australia is in the midst of an “energy crisis”, which has seen wholesale energy prices double in a year, according to an analysis by the University of Melbourne’s Climate and Energy College.

Construction costs have also risen over the past year and according to construction and quality surveying practice, Rider Levett Bucknall in its Q1 2017 Oceania Report, these rises will continue faster than inflation over the next four years. As a result, customers have started demanding the adoption of ‘green’ practices to reduce construction and building performance costs.

According to Dodge Data and Analytic’s World Green Building Trends 2016 SmartMarket Report, green buildings represent 34% of the total share of construction activity in Australia, proving that once-dismissed ideas are now gaining traction.

One of these ideas is Earthship construction, which uses recycled, reclaimed and natural materials to build off -grid, passive solar homes that do not rely on traditional carbon-heavy building designs and materials.

The Earthship construction principles were created by architect Michael Reynolds 40 years ago, incorporating specialised systems for thermal/solar heating and cooling, renewable energy, in-house sewage treatment, integrated water harvesting and food production.

After the 2007 release of the fi lm Garbage Warriors, a documentary following Michael and the challenges of building homes that do not match the structures of local building codes, the Earthship concept was brought to the public.

Part of a growing global selfsustaining architectural movement, there are now over 2,000 Earthships around the world. They have proved so successful that Michael’s company, Earthship Biotecture, has developed construction drawings for a global model Earthship that can be modified for almost any climate and adapted anywhere in the world. The global model was developed to move Earthships closer to mainstream housing and is designed to meet standard building code requirements.

Construction materials vary depending on the climate and what discarded or salvageable materials are available but key building blocks in most Earthship constructions include tyres, bottles, cans and reclaimed sheet metal.

This has lead to a misconception that Earthships are cheaper to build than conventional houses but for a house of a similar size, in terms of time and cost, the two construction methods are on par. However, Earthships are designed to be zero-waste, off-grid and selfsustaining, so once built they’re low cost and low maintenance.

With energy costs rising, this is a big drawcard for customers who see incorporating alternative building styles as a way to future-proof their homes.

Agari Farm, a group of natural builders and permaculturists, helped to facilitate the build of Australia’s first council-approved Earthship in Adelaide Hills, South Australia and recently began work on the first three-bedroom council-approved Earthship residence in Kinglake, Victoria on behalf of Daryl Taylor.

Daryl was one of thousands of people whose home was destroyed in the Black Saturday fire storm in 2009 and saw the re-building process as an opportunity to innovate. He spent five years gaining council building and planning approvals to build a global model Earthship, which began construction in October 2016.

“Councils are beginning to recognise Earthships but there are still challenges when you’re pushing something so alternative and emphasising offgrid, natural buildings with different foundations,” says Agari Farm interior designer and draftswoman Dani WolffChambers.

The Kinglake Earthship is being built using around 60-70% natural or recycled materials, including tyres, glass bottles, sand, clay, straw, salvaged 100-year old pieces of Australian hardwood and second-hand glazing. To obtain council approval, metal roofing and concrete slab flooring were required but Agari Farm is keeping their use in the construction process to a minimum.

The foundation of the Earthship is a thermal mass earth berm located at the south end of the building and held in place by a retaining wall made from tyres filled with site soil. The thermal mass and a North-facing glass wall form the basis of the passive heating and cooling systems. In winter the northern sunlight warms the thermal mass, which stores the heat and radiates it back as temperatures drop, while in summer cooling tubes, which are run underground through the thermal mass, release heat from the air to the surrounding soil, cooling the air as it enters the house.

“With these passive systems the Earthship stays a constant temperature and we’re going to be installing temperature and humidity sensors in the building to monitor this,” says Dani.

Typically, Earthships also incorporate food production, in-house sewage treatment and the ability to use water four times but some Australian council regulations restrict these practices.

The Kinglake Earthship does include an indoor planter for food production but because it’s located on an urban block it cannot contain in-house waste and sewage treatment, and black water is treated in a sewage treatment plant rather than a contained septic tank.

However, Dani says this could change as more councils begin to recognise alternative systems.

“Councils have begun to take permaculture into account in building approvals and a lot of new constructions in Australia are using alternative energy systems such as solar and passive ventilation. People are starting to get on board and alternative systems are becoming more common.”

A growing number of builds are now incorporating a mix of alternative and conventional construction methods, such as combining traditional wooden framing with cob walls made from clay, sand and straw.

Agari Farm is running workshops at the Kinglake Earthship, educating people about alternative construction, and Dani says there are usually three or four conventional builders at each workshop who are interested in learning how they can incorporate Earthship principles into their own builds.

“When people think of an Earthship they think of a tyre house that looks like a space ship but really it’s just a set of construction principles that can be incorporated into any conventional building design,” says Dani.