If you are buying land, building a house, looking at a major renovation or anything structural, it is critical that a soil test is undertaken prior to beginning the planning stage.
This simple step is crucial to know what conditions the structure must be founded in and can quickly clarify costs for the project.
On a recent project, one of our clients received the following information from their soil report:
“This site has been classified “P”, due to the large tree on the right hand side of the property. The roots of this tree have already infiltrated under the existing footings. A root barrier system should be incorporated prior to any construction.”
This means that the tree roots are causing upward pressure on the footings. The cost of this report was approximately $300. We are able to quote on a root barrier system for this. If no action had been taken, the cost of adding a root barrier system once the construction had started would have been a variation to the contract and an extra cost to the client. A much higher cost than organising a soil report.
Soil tests costs approximately $200 – $400 – money well spent.
Soil tests are standard practice when Architects and Designers look after as part of the engineering.
Always ask to commission a geotechnical investigation.
General Definitions Of Site Classes (Source: CSIRO):
A – Most sand and rock sites with little or no ground movement from moisture changes.
S – Slightly reactive clay sites with only slight ground movement from moisture changes.
M – Moderately reactive clay or silt sites, which can experience moderate ground movement from moisture changes.
H – Highly reactive clay sites, which can experience high ground movement from moisture changes.
E – Extremely reactive sites, which can experience extreme ground movement from moisture changes.
A to P – Filled sites.
P – Sites which include soft soils, such as soft clay or silt or loose sands; landslip; mine subsidence; collapsing soils; soils subject to erosion; reactive sites subject to abnormal moisture conditions or sites which cannot be classified otherwise.