With a low eco-footprint and high fire resistance, earth building is an old medium with modern appeal. 

Homes made from unfired earth – methods such as adobe, cob, pressed brick and rammed earth – now house up to half the world’s people, according to the Earth Building Association of Australia. And Victoria isn’t out in the cold: we have a long-standing tradition of earth building, especially in Melbourne’s north-eastern suburbs.

The association’s annual conference is being held in Eltham from Friday 14 to Sunday 16 August. It will focus on themes of sustainability, energy efficiency and bushfire resistance, and include tours of existing homes.

“Very few building techniques can match earth for low embodied energy,” says vice president Ray Trappel, an architect from NSW. It’s even possible for mudbrick walls to have negative embodied energy – to save energy overall – he says, if they’re made from intercepted excavation waste (which avoids trucking the material to landfill).

The potential for extra fire resistance is another benefit. A 250-millimetre thick mudbrick wall can achieve a high, four-hour fire rating. “A lot of people are considering using earth in their rebuilding (after the January bushfires),” Mr Trappel says.

If you build yourself, earth walls can also save you money. “It’s quite realistic to save up to $50,000 by not buying your bricks and not getting a bricklayer to lay them,” he says. He acknowledges that it will take hard work, but says there are many courses and resources available to guide your toil. “The association helps people share knowledge on all sorts of issues, like the most efficient ways to make bricks and the connecting and finishing details.”

But this kind of building is not just for the DIY set. There’s also an established professional industry. “A mudbrick house can be built cheaply using prefabricated technologies, or it can be a hand-crafted, top-end product,” says Greg Slingsby, a Melbourne builder and president of the Nillumbik Mudbrick Association. “Contemporary building styles have changed the image of mudbrick housing.

“We attract people who want to spend money on a craftsman-built, quality home. We’ve got a huge portfolio of modern houses that are architecturally exciting, with every state-of-the-art convenience,” Mr Slingsby says.

Earthen dwellings have a lot of thermal mass – the heavy walls absorb and store heat, which helps to curb the extremes of summer and winter – but they don’t record high insulation ratings. When the five-star regulations were introduced in Victoria, the earth building industry questioned the rules for failing to fully consider the benefits of thermal mass in external walls.

Mr Slingsby says that while the rating program has improved, it still doesn’t reflect the high comfort levels and low energy needs of residents living in mudbrick homes.

“Earth building, to my mind, is the most eco-friendly building medium there is,” he says. “The internal environment is healthy, low in humidity and comfortable all year round. These homes embody the very notion of green building.”

There are smart and inexpensive tricks to trapping heat indoors.

When the weather’s cold, ten times more heat escapes through standard windows than through insulated walls. That means your mid-year heating bill is vanishing through the glass.

But there are quick and simple fixes to help block the cold, says Amber Chamberlain from environmental consultancy Ecovantage. “Just covering up your windows in winter helps stop heat loss.”

When it’s cold outside, warm air turns into a chilly draught as it draws near exposed glass. To cut the heat flow, you need to trap a layer of still air next to the window pane.

“Curtains and blinds need to fit snugly and to be heavy – the heavier the better,” she says. “A good rule of thumb is that the more light coming through, the more heat that’s also being transferred.” Go for curtains that stretch below and beyond the sides of the frame, touching the wall or floor, and install pelmets (seals above the curtain or blind) to stop air at the top. You can fashion temporary pelmets from anything that fits – try cardboard or a thick scarf.

If heavy drapes aren’t to your taste, Ms Chamberlain suggests honeycomb or cellular blinds as a good alternative. “They trap a small amount of air within the blind itself, which acts as an insulating layer, and they still allow light into the home.” It’s wise to avoid gappy vertical and Venetian blinds.

Kirsten Johnstone, from Eco Edge Architecture + Interior Design, maintains that with careful thought, window coverings can be attractive as well as functional. If you’re building your home, she recommends designing window frames to fit recessed blinds. “You can create a channel that holds the sides of the blind within the frame,” Ms Johnstone says. “I think that’s a good solution, rather than the voluminous curtains that remind me of my Grandma’s house.”

She also says that, for homebuilders and retrofitters alike, pelmets need not be eyesores. “A minimal approach would be a small, painted box above the window or within a frame recess, painted out so it matches the wall. Try not to attract attention to it.”

Another way to improve your windows’ performance is by retrofitting double-glazing. Ecovantage suggests that DIYers try Clear Comfort, a membrane taped to the frame and made taut by shrinking with a hairdryer. “It’s virtually invisible and traps a layer of air in between the film and window, á la double-glazing,” Ms Chamberlain says. A 10-metre kit costs only $180.

For the less handy, companies such as Magnetite and MagicSeal sell secondary acrylic panes that attach to your window frame using magnets. “This solution is much more permanent and durable than DIY film. It’s more expensive, but still a fraction of [the cost of] double-glazing,” says Ms Chamberlain. The cheapest option of all is recycled bubble wrap, stuck on with the smooth side facing the room. “The little bubbles are perfect mini double-glazing cells, so why not use it on your windows?”

See related article: Windows

Both owners and tenants can benefit from retrofitting their houses.

“If a landlord and a renter were in a conversation,” says Jessica Steinborner, from Moreland Energy Foundation. “I think they’d agree that we should do something about sustainability, and that our homes are a good place to start. But how do we actually get the changes to happen?”

It’s tricky to even begin that discussion: communication between landlords and tenants is often fraught and property managers don’t always help.

As a part of its Energy Efficient Homes Package, however, the Federal Government has given all parties a reason to get talking. Owners are now eligible for up to $1000 to install insulation and $1600 to replace electric hot water heaters with solar units.

Landlords can also get rebates on rainwater tanks and grey water setups, and claim tax deductions on eco-maintenance around their properties. What’s more, from May 2011, they’ll be required to reveal the dwelling’s energy performance at the point of lease.

These steps help reduce the so-called split incentives, whereby property-owners pay for big-ticket items, but tenants get the lower bills. Ms Steinborner argues that, in any case, owners do benefit from their investment. “It improves their property – not just the resale value, but also the ability to get long-term tenants. Renters understand that it will be a far cheaper and more comfortable house to live in.”

Moreland Energy Foundation organises free workshops for local renters who want to green their homes. The good news, Ms Steinborner says, is that people can slash their eco-footprints without altering their houses. “About 30 per cent of household energy use is related to behaviour; things like closing the curtains when the sun goes down, using external blinds in summer, shortening showers, washing clothes in cold water, setting thermostats correctly and turning lights off.”

Renters can also install compact-fluorescent light globes and choose efficient appliances without bothering the owner. But before they make other changes – including switching showerheads – they should get approval. “There are small things that often people won’t do because they’re worried about their tenure, and nervous about contacting their landlord,” Ms Steinborner says.

With energy and water prices rising, low-income renters are likely to be the first to suffer. Last year, a group of Melbournians started Just Change, an organisation dedicated to addressing these equity concerns. “We put up to $1800 worth of energy efficiency retrofitting into a house,” says Dougal McInnes, “and ask for up to a one-year rental freeze (in exchange).”

He says it’s been difficult to find homes where all parties are willing to be involved. “We’ve found that real estate agents are the key, both to gaining consent from the landlord and access to the tenants.” There’s a lesson for aspiring eco-friendly tenants and owners: get your property manager onside first.

For oodles more tips and information, browse Environment Victoria’s excellent Victorian Green Renters’ Guide. Also, check out Green Renters, a blog for environmentally conscious tenants.