Soil Testing is an important aspect when building a new home, and is completed by a Geotechnical Engineer.

The tests are carried out to understand how reactive the soil is and to ensure that there aren’t any hidden chemical or physical conditions on the site that might damage the house.

The tests are also used to help the structural engineer correctly design the house footings.


The main soil problems found are soft soil, loose soil, overly wet soil and clay soil (reactive clays). Soil reactivity refers to how much the soil on the site is likely to move, expand or contract.

Reactive soil can easily cause a lot of damage to the house, especially if the house is designed using the wrong type of concrete slab.


To get Familiar with the soil classifications, below is a list with a brief definition.

Class A: Stable, non reactive. Mostly sand and rock sites

Class S: Slightly reactive clay. May experience slight movement.

Class M: Moderately reactive clay or silt sites. May experience moderate movement

Class H1: Highly reactive clay sites. May experience a high amount of ground movement

Class H2: Highly reactive very high ground movement

Class E: Extremely reactive sites. May experience extreme amounts of ground movement

Class P: Problem Sites.  The ability to evenly bear a load is very poor, as a result could cause mine subsidence, landslip, collapse activity or coastal erosion.

Class D: Deep movement in the soil due to deep variances in moisture.


The soil under your home is there for the life of your building, so it is best to get the test done to ensure the foundation is designed correctly. In most cases it is compulsory to have the soil tested prior to building.


Have a look at our facebook page  and our website for more information