Tim Oldham has been working on the house build since January 2018. Photo / Stuart Munro
Tim Oldham has been working on the house build since January 2018. Photo / Stuart Munro
This summer the Chronicle is bringing you another look at some of the best content of 2019. This story originally ran on March 26, 2019
A modest house being built on a windy flat high above the Whanganui suburb of Putiki is a flagship project in alternative and natural building.
It will be very quiet, very stable in temperature and humidity, "kind of simple and very relaxing", builder and architect Tim Oldham says. Its large, double glazed northern windows will let in lots of winter sun to warm its earthen walls and floors.
The aim of the building is simplicity and economy. Whoever ends up living in it will be surrounded by natural materials - earth, wood, limestone and wool - a minimum of concrete and a corrugated iron roof.
The house build began in January 2018, at Te Riri a Te Hori, on a subdivided piece of freehold Māori land in Hewitts Rd. It was to be a template for future houses there, in an eco-kainga led and inspired by the late Ari Bailey.
Momentum faltered when she became ill with a brain tumour and died in September last year - but her partner of 20 years, Phillip Baertschi, her daughter Zoe Cochran and builder Tim are keeping the project alive.
"It really needs to get finished as a showcase. I'm certainly prepared to do that," Tim said.
He's an architect and did the drawings for the house, which was designed by New Zealand's foremost earth architect, Graeme North. Tim moved from Warkworth to Whanganui for the build, bringing his own tiny house on wheels.
Builder and architect Tim Oldham came to Whanganui with his own house on wheels. Photo / Laurel Stowell
The energy behind the whole project was Moari (Ari) Bailey, a high-earning IT expert, enthusiast, idealist, dreamer and people person. She got a $140,000 grant from the Ministry of Māori Development (Te Puni Kokiri) for power, site works and tracks and earned enough for the rest of the project through her high-paid contract work.
She estimated it would take $250,000, and volunteer help, to build the house, and she counted on getting more contracts. Since her death money has been tight. Tim has worked unpaid at times and some of the spend now is Ari's life insurance.
One of the unique features of the house is the light earth infill for its internal and external walls, untried elsewhere.
Since Ari's death Phillip has been spending most of his time working at the house, sometimes completely on his own.
Phillip Baertschi and Zoe Cochran, with two-year-old Lewis, are continuing work on the Te Riri a Te Hori earth build. Photo / Laurel Stowell
Ari's daughter Zoe is a chef, with a job, a two-year-old son and a partner in New Plymouth. She's been spending half her time in Whanganui to work on the house.
She bakes for a New Plymouth business on Monday and Tuesday, then brings son Lewis to Whanganui and cooks for volunteers on the project, hosting volunteer sessions on Thursday evenings from 5.30pm, and all day on Saturdays.
Besides Tim, Phillip and Zoe, you might find other people at Te Riri a Te Hori - volunteers, some of the "wonderful people" who have come to help. Graeme and Lyn Pearson and John and Helen Wilson have been stalwarts.
Volunteers Lyn and Graham Pearson arrive with gloves ready to make a mix. Photo / Laurel Stowell
There's also the site supervisor, Lady Marmalade, a female ginger cat.
And there have been lots of "tourists", Phillip said, people who are curious about the project and want to see what's going on.
The plateau the house sits on is poorly drained. The building's rectangular foundation is made of free-draining Rangitīkei River stones. On top of that there's a reinforced concrete ring beam on concrete piles.
The framing is locally milled macrocarpa timber, with a 300mm wide infill of light earth between the frames. The infill is made of clay dug from the foundation and from the holes made for water tanks.
Some of it is a yellow-grey and some is darker brown. It's first soaked in water for a day or two to dissolve lumps, then whizzed up with a large handheld blender, turning it into a smooth, creamy mixture.
(From left) Zoe Cochrane, visiting French cyclist Jerome, Phillip Baertschi and Ann Handley mix mud and wood chips to make wall infill. Photo / Graham Pearson
That slurry is combined with wood shavings and straw, either hand mixed on a wooden table or churned up with a modified rotary hoe in a wooden trough.
The light earth is hand packed between plywood barriers to fill gaps in the framing. Later the plywood is removed, the infill dries and the plywood is used elsewhere.
Drying usually produces cracks and gaps, which are filled with fresh clay mixture. The whole surface can then be coated, inside and out, with lime plaster.
Making the plaster is something like an explosive chemistry experiment, Tim says. Limestone is quarried and burned to become "quick lime", calcium oxide, which is very highly reactive and caustic. At the site people wearing protective gear mixed it with water.
When water is added it boils violently, producing heat and steam, then settles down into "lime putty" and can be stored indefinitely. Later it will be mixed to a mortar with sand and troweled on to the finished walls. Once there it will harden, by absorbing carbon dioxide from the air, and become limestone all over again.
"It's an incredible material," Tim said.
Eucalyptus branches cut on a neighbouring property have been used for roof trusses. Photo / Stuart Munro
Roof trusses at the house are the rounded branches of eucalypts milled on a neighbouring property. The ceiling will be stretched hessian, coated with clay. Between it and the corrugated iron roof will be wool insulation.
Phillip lays out bottles saved for floor insulation. Photo / Stuart Munro
Inside the concrete ring beam a layer of pumice sand will be smoothed out to begin the floor. On top of that go 5300 wine bottles, sourced through the Sustainable Whanganui Trust and Caroline's Boatshed Bar & Eatery, closely packed and lying on their sides. On top of them will be a 150mm layer of light earth, finished with a layer of earth plaster oiled to a darker brown.
"Oil sets the clay and makes it impervious to water and wear. It goes like old fashioned linoleum."
The windows on the north side of the house will have recycled aluminium frames, and the roof has generous eaves, especially to the south, to protect the earth walls from weather.
Days are getting shorter now, and finishing the light earth infill will have wait until next summer. Tim didn't think the build would take so long, and as well as finishing it he's looking to start new projects - especially in supervision and design.
He says in New Zealand earth building mostly happens in places where there are practitioners who enthuse others. It's popular with alternative lifestylers, in Nelson and Golden Bay, and in Northland.
Putiki has its own little enclave, with houses built by the late David Jones. Terry Trotter's more recent rammed earth house is visible across the plateau from Te Riri a Te Hori.
Earth building is probably not the answer to New Zealand's need for affordable homes, Tim says, because it uses so much labour. But it could be an answer in places where there aren't many jobs and people will work for lower wages or for love.
The house at Te Riri a Te Hori is likely to be lived in by Phillip and by Zoe, at least for a while. What will happen after that is unknown. Without Ari's drive and enthusiasm her plans for rongoā gardens, orchards, a commercial kitchen, more houses, workshops and retreats may never happen.
The Te Riri a Te Hori wetland near SH3 is home to birds, insects and eels and planted with harakeke and reeds. Photo / Laurel Stowell
But her first venture on the land, a constructed wetland linked to Awarua Stream, is well established and needs little ongoing help. The harakeke, reeds and raupo have rocketed away, and frogs, dragonflies, eels and pukeko appreciate the water.
A former milking shed on the property now has a bunk room and shower, so that anyone who wants to help can stay over. Phillip says this could be an ideal opportunity for someone who has free time and wants hands-on experience in earth building.
EARTH HOUSE AT TE RIRI A TE HORI
+ three bedrooms + an average 120 square metres in size + estimated cost $250,000 - mostly labour + on freehold Māori land with five owners + intended as template for future builds
