Poured Earth

This technique involves mixing water with the earth until you can pour it into moulds without creating voids - typically about cake-mix consistency. The mix is placed into moulds set up directly in place on the wall, and once it has set the mould is removed.

The mix used in this technique has a much higher moisture content than rammed earth, so the shrinkage is potentially much higher. This means that the soil mix has to be carefully controlled to avoid unsightly and structurally damaging cracks opening up as the material dries. Sometimes the moulds are set up in a castle like pattern, and the intervening gaps are filled with a second pour after some shrinkage has taken place with the setting of the first pour.

Shuttering systems developed in Australia are now available here. They limit the size of each poured earth section, and by controlling the sequence of pours fine walls can be created. The shapes of walls are constrained by the shuttering used, but they can be quite flexible in their arrangement. The surface of the work is often dominated by the size of the cast units, and is usually fairly smooth unless rubbed or modified after the shuttering is removed.

Often this technique uses around 10% cement in the product to assist with durability and shrinkage control. Appropriate tests for this technique are detailed in NZS 4298.