|
|
|
On the Road Again
MY SISTER and brother-in-law have a farm in southern New South Wales at Tullakool, a rice-growing district in the Wakool Shire around 30 kilometres from Barham. So when they needed to find more room for their growing family, rice straw seemed to be the obvious alternative building material. They had a 20 year old transportable home that had been moved to their property in two halves when they married 16 years ago. It had served them well but was poorly positioned and feeling the pressure of three children plus one on the way. Bold plan After considering the alternatives we chose to use what was available to us: rice straw bales and the existing house. The bold plan was to move the existing house from its sinking stumps to a new site more convenient to sheds, yards and stables, positioned to take advantage of the sun and to raise it 2.6 metres in the air. Although this was to be the first strawbale house in the shire, council approval was relatively straight forward, requiring an engineer’s certificate for the slab and support structure and some extra detail about the construction technique of the straw bale walls. The book The Straw Bale House was an invaluable resource here.
Conveniently, the rice harvest was in progress as work on the house began. After the grain was harvested we mowed the stubble just above ground level and got long lengths of straw for baling. We used a baler to compress the straw into bales. We also made some half bales to complete wall ends and corners. We stored the bales in a hay shed on the farm before placing them in the walls. Lift-off Once the new site had been selected a mound was prepared for the slab, formwork put in place and the slab poured. We put up a steel frame on the slab using steel support posts, beams and bearers. Before we moved the house, we removed the kitchen and laundry to make way for the stair well and the new baby’s room. Next we installed the insulation: R3.5 wool/polyester blend batts. French doors replaced windows on the north wall. Windows on the east and west walls were taken out and reused elsewhere in the home. Basically anything that could be done on the ground was completed before lift-off. On the road again The day of the move dawned with rain threatening. After a few showers while manoeuvering the beams under the house, the clouds cleared to allow the cranes to lift the house while the low loader was backed under the swaying structure. The house was moved in one piece using three cranes. Once on the truck it was driven three km to the new site and by simply driving out the gate at the old site and into the new site the house was turned 210 degrees to begin its new role as a passive solar home. Darkness was almost upon us as the last of the lifting beams were taken out and the house came to rest, looking vulnerable and fragile on its elevated perch.
We then began extending the roofline, following the existing pitch to cover the balcony and roofing the verandah on the south side with the aim of providing shelter while the strawbale walls were constructed. Window and door bucks were placed before the first bale was laid. The first course of bales is impaled on reo bar protruding from the slab. Lengths of reo bar were hammered into the bales every second course. The walls were tensioned in two stages: at the first floor level and again at ceiling level. The gable was filled with bales and bundles of straw to fill the angles. Rendering We secured chicken wire netting to the bale walls inside and out by pushing high tensile wire pins into the straw. The pins were bent in such a way that they would push in easily but resist pulling out. I found a U-shaped pin worked best. We formed a length of wire mesh for each corner, which served two purposes. One: reo to provide a tie for the wire netting and secondly, to provide a pointed edge on the corner when it came to rendering. Lachlan Bourke of Quick Straw Spray Render in Bendigo sprayed on the render. This period of the house was rather intense with the render job completed over seven days. There are three layers of render: the first two done with regular grey cement with the final coat using white cement on the internal walls. The external walls used grey cement with an oxide powder called Deep Buff to give a rich terracotta colour. With the colour of the render when it is first applied being a deep orange red the nickname for the house among the locals at this point was Ayers Rock! Finish We used lime wash on the interior rendered walls, made up from lime putty left over from the rendering, with a hint of the deep buff oxide blended in to give a soft almond tone. The plasterboard walls were painted to match. The balcony shades both the upper and lower northern windows during summer while allowing the sun to penetrate deeply into the house during the colder months.
End result Now the home has double the floor space, rooms for each of the children — including the new addition, young George — and the comfort of sensible energy efficient design. |
Bales
Laying
The slab floor experienced the rigours of construction unsealed. We bought a Wattyl product called Proclear to seal the concrete before we moved in. Before we sealed it we brushed on a weak solution of the deep buff oxide and roughly ragged it. Then we applied the first coat of sealer. A second coat contained ten per cent of a stain called Koala Blue and then the final coat of clear sealant was applied. The result is a durable finish with a visual depth akin to marble.