By Catherine Smith
The word "sustainable" in real estate is overused. However, when homeowners Gus Anning and Sarah Rowe began exploring how to build a home for themselves and their three children, they really dug deep — literally and figuratively — for a building type that was genuinely self-sufficient for energy, water and waste. After three years of research, two years of planning and nine months of building, their home — dubbed Te Timatanga, or "beginning" in Te Reo, one of New Zealand's official languages — was unveiled to viewers in the first New Zealand season of the television show Grand Designs.

At a Glance:

  • Who lives here: Sarah Rowe and Gus Anning and their children Bryony, 14, Toby, 12, and Whio, 4
  • Location: 3
  • Size: 2,580 square feet (240 square meters) on 2½ acres (1 hectare); four bedrooms, three bathrooms and an atrium
  • Building designer: Harriet Pilkington of Young + Richards

Like many people, Rowe and Anning knew the overarching principles of sustainable design: using the sun to warm the house, collecting their own water and utilizing recycled materials to lower the house's embedded energy. It also helped that they were starting from an ideal place, as Rowe's parents had given them land nestled in a valley on the eastern slopes of the Coromandel mountain range, with the perfect north-facing orientation and a gentle slope.

The community, just over an hour from Auckland, is in an area known for its many alternative lifestyles. This worked in the couple's favor, as many of the skilled craftspeople, helping hands and materials serendipitously came their way just when they needed them.

Their three years of research found its focus when the couple came across the movie Garbage Warrior, which focuses on the biotecture of Mike Reynolds, the American founder of the Earthship building system. The passive-solar homes use natural and recycled materials to create a thermal mass that stabilizes temperature, paired with renewable energy and water systems.

The family's first piece of luck was Anning spotting a passenger on the ferry he skippered wearing an Earthship T-shirt. Turns out there was a hands-on building session with the Earth Building Association of New Zealand running in Christchurch that summer. Not deterred by the fact that it was already booked up, Anning turned up at the site. By the time the organizers realized he was an interloper, he was already working with the tools. The couple also visited an early prototype house, the Gubb home in Ngaruawahia. They realized that it takes a lot of work to build a modern home to meet today's building codes.

Although they had the perfect site, the couple recognized that the rainy Coromandel weather posed more challenges than the desert environment Earthships are usually built in. Right from the beginning, the pair was in discussions with their local council, which was keen to make sustainable housing doable in the community. Earth houses built from mud bricks or straw were already not uncommon, but the couple's plan also involved filling recycled tires with earth and using a passive heating and cooling system.

As it happened, their chief council contact had just completed training in sustainability and linked them up with consultant Graeme North. He worked as an adviser to Anning and Rowe's architectural designer, Harriet Pilkington, and as peer reviewer for the council to ensure the building met code.

In one of his (many) past lives, Anning had won an architectural designer award, so the couple were happy to sketch out their first ideas for the house before calling on school friend Pilkington to refine the designs and create working drawings for council approval.

The first principle of the Earthship — "a machine designed to collect heat and distribute it," as Anning says — was the atrium. With its wall of windows angled at 70 degrees (that angle is determined by latitude) it collects the sun that comes into this front section of the home. The bedrooms and bathrooms are aligned along the length of the corridor behind the atrium.

The combination of windows above the bedroom doors, underground venting tubes behind the rooms and Velux windows along the atrium allows the homeowners to draw cooling air around the rooms in summer or admit and circulate solar gain for winter heat.

The couple decided the private rooms would have glass walls so they could enjoy the atrium fully. The curving plant beds are sufficient for privacy and provide an attractive view.

They also veered away from Northern Hemisphere designs by opening up the kitchen and living rooms to the outdoors for the indoor-outdoor living Kiwis crave.

At the western end of the house, Pilkington included nearly 645 square feet (60 square meters) of covered terrace — a gorgeous spot for viewing sunsets and sheltering from the sometimes-rainy summers.

Anning and Rowe decided early on to turn the construction of their home into an Earthship workshop, to share skills, get the job done quickly in the summer and contain building costs. Over the summer of 2015, dozens of paying volunteers were schooled in the techniques of stacking some 1,100 tires, filling them with clay dug from the site and plastering them to form the walls. The volunteers were led by project managers Ben Garratt and Rosa Henderson (of Sculpted Earth), whom Anning had met at his first Christchurch workshop. Rowe worked part time while feeding the workers and laboring alongside them; Anning tapped contacts for resources and finishes.

The southern side of the house is dug into the bank, with layers of waterproof membrane carefully inserted between land and tires to ensure no moisture seepage. The subfloor was lined with mussel shells (a local waste product, adhering to the couple's philosophy throughout the construction process) and more waterproof membrane before concrete was laid.

For the interior walls, the family scored secondhand mud bricks that were left over from a friend's earlier building project. Nothing was wasted: Even the broken bricks were mixed into a slurry for plastering the walls.

Accumulating enough tires for the build took around six months. Rowe and Anning had watched a loaded tire truck drive by their property for weeks before catching the driver at a local cafe and negotiating for the tires that were destined for the garbage dump. Like many participants in the project, the driver was delighted to carry and stack the four different sizes of tires, happy that they were not going to become landfill.

Naturally, the kitchen was to become the heart of the home. In addition to a gas oven (fueled by gas bottles, the only energy brought in from outside the house), Rowe and Anning were determined to have the modern version of the old-fashioned Rayburn range. In the winter its attached pipe system heats the house's water — there is always a pot of stock simmering on the stove — but the house is so warm the heat is more for psychological comfort.

Beams for the roof came from Natural Log Homes, a company from New Zealand's South Island that works with local Douglas fir. When the family was puzzling over roofing systems, their architect, Pilkington, introduced them to the concept of structural insulated panels. Commonly used for industrial coolers, the 8-inch-thick panels bond roofing metal, an insulated core and a ceiling panel in large sheets that Anning says were "awesome" to install and keep clean.

Despite its super efficiency, the family wanted their house to feel warm and homey. They, and their visitors, rave about the embrace of the house.

The couple worked with solar consultant Jasper Campbell of Metalcraft Roofing to settle on the best system for their home. At the moment, they do not use batteries to store excess power but feed it back to the utility company's grid. While they have not signed up for any monitoring studies, Anning and Rowe are still fine-tuning their energy use, determined to get their monthly bill, currently about $50 for hook-up charges, down to zero. They plan to do this by upgrading appliances and checking out smart meters and other systems as they become more affordable. The wood fire is purely for ambiance, as the house stays a consistent warmth (and dryness) year-round.

Anning and Rowe say they are still working on achieving their sustainable dream. Their next project is to cover the concrete floor. Impending winter weather and budget meant that they left the floors as concrete, instead of their preferred rammed earth. They are now investigating building their own kiln to make and fire floor tiles from earth from their property. In the meantime, the black-oxide-stained concrete is good for solar gain.

Rowe and her friends foraged for bottles to make the plastered feature walls, carefully selecting and cutting the glass to create soothing swaths of color that enliven the walls around the atrium and their en suite bathroom. The custom hexagonal doors were built by Bob van Pearce.

As well as providing a year-round tropical ambiance, the atrium garden is an essential part of the water system. Rainwater is used for cooking and drinking, and the greywater from laundry and showers is filtered into the planter, which starts shallow at the front door end and gets deeper as it runs through the house.

River rocks and peat moss filter the flow (with plenty of Daltons potting mix, customized with coconut husk), and a small bilge pump recirculates the water back to a raised kitchen garden. After greywater is used for flushing the toilets, the black water is fed into a worm farm septic tank system. This uses worms and other natural means to process the waste and turn it into fertilizer; this is then further purified and treated, and then returned to the soil and used to irrigate the 20 heritage fruit trees in the orchard.

The plants' photosynthesis produces oxygen for clean, healthy air, as well as moisture to help maintain comfortable humidity levels year-round.

All the bedrooms in the home open onto the atrium. Again, the couple was lucky to score old French doors that were being thrown out from a vacation house renovation, to add a sense of charm and history to their home.

The master bedroom en suite wall was another labor of love by Rowe, helped by friends and children.

To continue the natural feel of the house in their bathroom, Rowe found terrific random stone tiles for the floor and shower walls from Island Stone. The vanity features recycled and raw timbers.

Using organic materials for fixtures more commonly made out of plastic or enamel was part of the couple's ethos. Here, the basin is petrified wood, sitting on another custom-made vanity.

The mix of colors was carefully considered by Rowe as she assembled the bottle walls.

The main family bathroom opens to the luxuriant garden, through a feature wall complete with another custom-made hexagonal-cut door and surrounding glass.

The walls are finished in a tadelakt plaster common to Morocco and North Africa. The traditional flat lime plaster is waterproof enough to be used as an exterior finish or in bathroom wet areas, and it has the smooth curved look and natural tints that complement the mud-brick walls in the rest of the house. The plaster was burnished to a smooth finish over three days in a satisfyingly hands-on process.

The children's rooms are big enough for desks and hangout areas, and enjoy great natural daylight from the atrium windows.

The build required some new thinking from many of their suppliers, but Anning says companies such as Metro Performance Glass helped him solve problems with the angled woodwork and runoff to the ground.

Since it appeared in the first New Zealand season of Grand Designs, the house has attracted a lot of attention. Anning and Rowe are full of praise for the support of their local Thames Coromandel District Council and are so thrilled that they have been able to host tours for building managers from councils around the country.

The couple also has been renting out the house on Airbnb during past summers while they travel. (Anning spent the summer with the Antarctic Heritage Trust restoring Hillary's Hut.) Visitors are captivated by the serenity surrounding the house, as well as by the house itself. Anning says most people can't get over the lack of light pollution and are entranced by the stars in the clear skies.

While the couple did not want to stint on systems and finishes — Anning estimates the finished building cost at around $80 to $93 per square foot — the innovative energy and water systems mean that running costs for the house are minuscule. But what has really delighted them is the quality of life in their Earthship: the comfort of being surrounded by earth and natural materials, as well as the glorious sense of solidity and connectedness. And they are pretty sure they face a lifetime of helping other people build their own Earthship dreams.

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