Different soil classes have various capacities to shrink or swell (also known as movement), and this affects the way the footings for your home or structure need to be designed. Your soil type will also guide the landscaping and drainage requirements for your block. According to the Australian Standard AS2870, soils in Australia are classed into the following:

Ideal soil types to build on are A and S. It is not impossible to build on the other classes, however, it is definitely more costly to do so, and problematic sites call for careful management over the life of your building. This is why it is wise to perform a soil test prior to signing any contracts to purchase land, or commencing a build or renovation. A soil test may cost a few hundred dollars but could save you thousands in the long run.