Rib Raft Foundation

Many new houses in Christchurch are using Rib Raft foundations, because they cope better with earthquakes.

The ground is dug out to about a meter deep. A plastic sheet is put in, and then layers of shingle (heavy to light).

 The shingle is rolled hard like building a road.

 The hard shingle becomes the base for the floating foundation.

The polystyrene squares separate the ribs, which are filled with reinforcing steel.

Concrete is poured into the ribs and over the entire foundation.

The finished foundation, ready for the timber framing to be put in place.