Whare Uku
Ahikaaroa Trust
100m2
$150,000
The Project
This project is a 3 bedroom whare uku (earth house). The walls are constructed from rammed earth made through a process that involves ramming an earth mix, consisting of mostly earth from the site in which the house is located, mixed with sand, muka (a fibre that comes from flax), and a little concrete between panels that provide the formwork for the walls. The walls are 200mm thick and sit on top of a reinforced concrete slab, which is covered by an earthen floor. A corrugated iron gabled roof rests upon a concrete ring beam, which wraps around the top of the walls. The ceiling is built with macrocarpa wood that is left exposed, adding to the beauty of the interior space.
The building is essentially a large rectangle with a simple gabled roof that is oriented to the North, causing all the rooms in the house to receive all day sun with the exception of one bedroom and the bathroom. The simple shape of the house and its position on site has both kept the costs down and meant that it is pleasant to live in.
Earth walls are known for their ability to transfer heat slowly. If the wall is thick enough and oriented in the right direction (which is the case for this whare uku), the walls are heated up throughout the day and this heat is then released throughout the night. This means a cool indoor temperature during the heat of the day while the walls are warming up, and a warmer internal temperature throughout the night as the heat is released from the walls.
Earthen walls are also known for providing a healthy living environment as they absorb humidity from the air when left unsealed which is the case on the interior of the walls. The exterior walls have a lime wash finish which helps repel moisture.
The cost of this house was $150,000 and that included the site works, the energy systems including the solar power, and an eco waste system. The build time for this house was about two and a half months although the actual timespan of the construction was longer due to needing to meet various council requirements.
The Ahikaaroa Trust has consented designs for 1 and 5 bedroom whare uku of a similar nature.
Low Cost
There are several factors that contributed to the low cost of this construction. One is that the materials for the home were for the most part inexpensive and locally sourced, with the earth coming from the site itself and the timber from down the road. The community also got involved in a big way which helped in keeping the costs down. Mr Taipari has noted that more efficient techniques have been developed since this build that require less manpower, which in turn equates to being able to continue to provide these houses at a low cost.
Another factor that kept costs down was the simplicity incorporated into the design of the building such as its simple layout, roof, and details. One of the largest costs was the glazing for the windows and double-glazed sliding doors.
In addition to the building itself being relatively low cost, the building also has solar panels and functions off the grid so there are no external electricity costs. Heating costs are also kept to a minimum because, as mentioned before, the house is orientated north, letting the sun do the work of heating the house up.
Rueben Taipari and Ahikaaroa Trust
Rueben Taipari presently chairs the Ahikaaroa Trust, which is a Northland housing provider set up by himself and his wife, Heeni Hoterene, in 2014.
A trip to Europe in 2008 got the couple interested in the benefits of rammed earth housing. While in Europe, they stayed with a family whose earth home had been in the family for generations and illustrated a solution to both Taipari and Hoterene who were concerned about the wellbeing of future generations. This experience drove them to get involved in making rammed earth construction a legal reality in Northland, using their own home as an example for their local council to evaluate.
Though the Trust also caters for non-rammed earth houses, in his experience Taipari notes that rammed earth is “...definitely cheaper. The money I would have invested in a standard crap house could make a really awesome earth house. It cost about $150,000 for a three-bedroom earth home including roading access, the home, alternative energy, an eco-waste system, and a permaculture plan.” ~ Reuben said in an interview for Stuff.co.nz.
Contact
If you would like to learn more about what Ahikaaroa Trust is doing with whare uku or hear about the other initiatives they are involved in head to manawhenua.com which is also where you can contact them.
