Interaction between shallow foundation systems and clay shrinkage

The consequential effects of clay shrinkage and swelling occurs in numerous centres around New Zealand, particularly in the Auckland region, where it is a common problem for houses of brittle construction (i.e. brick veneer and plaster exterior) constructed on shallow strip or pad foundations. The extent and magnitude of the shrinking and swelling of plastic clays is predominantly related to seasonal variations within the soil-moisture regime. Shrinkage can also be exacerbated by the presence of high water demand tree roots. The resultant movement can be differential settlement and building distress.