About Site Classification
A Site Classification is carried out in accordance with the Australian Standard AS2870: “Residential Slabs and Footings”. Classes include S (slightly reactive), M (moderately reactive), H1-H2 (highly reactive), E (extremely reactive), or P (problem site). Classes S, M, H1-H2, and E refer generally to sites in which clayey soils will form the founding strata.
The classification indicates how reactive the clay subsoil is to changes in moisture content. The reactivity (shrinking and swelling) of the clay can have a significant impact on the footings / slabs of a building slab which need to be designed to counteract the movements of the clay soils, otherwise damage (cracking) of the house may occur.
Sites classified as Class P may present difficulties for the proposed construction. The P classification often suggests deep and/or uncontrolled fill, which cannot provide suitable bearing for the house. In these situations, the house is either founded on the stable materials beneath the fill (i.e., deep footings / piers), or the fill is removed and replaced with compacted, controlled fill.
CQ Soil Testing are able to provide site classifications for either large subdivisions or individual allotments. We have the facilities to carry out both the fieldwork and laboratory testing necessary for a site classification, whilst our association with professional engineers are able to interpret the results and provide the appropriate footing designs in a short period of time.