Soil Tests: What to Get Right Before You Design
A soil test can tick a compliance box and still miss the information that actually protects your budget — the difference comes down to a handful of specific things worth checking for.
A soil test that satisfies council is not necessarily one that protects your budget — the difference comes down to a handful of specific things worth checking for before the drill rig leaves site.
Three bore locations, minimum
A single bore hole tells you the site classification at one point, not across the block. Reactive or variable soils can differ meaningfully within the same site, so a genuinely useful report covers at least three test locations spread across the building footprint — not one convenient corner. Where truck-mounted rig access is available, take it; hand-auger testing is a reasonable fallback on a constrained site, but a mounted rig generally reaches greater depth and gives a more reliable read on what is actually underneath.
A bore where the pool will sit
If a pool is part of the concept, even loosely, it needs its own bore hole — not an assumption carried over from the house footprint’s results. Pool excavations go deeper and carry their own structural and hydrostatic considerations, and a soil test that skips this spot is deferring a cost question rather than answering it.
Design to the results, not around them
The real value of a soil test shows up once the design actually responds to it — footing type suited to the real classification, cut and fill worked out to minimise unnecessary earthworks, and retaining addressed as part of the design rather than discovered as a variation later. Where rock is present, this matters even more: designing around it, rather than through a deep excavation into it, is often the difference between a straightforward footing and a significant, avoidable cost. See why building projects go over budget for how these decisions compound if they are not addressed early.
A soil test is one of the specific things worth having in hand before an early cost conversation — see what to have ready before a Feasibility or Foundation engagement for the fuller list. For the testing itself, APOD Soil Testing is a Brisbane-based geotechnical firm we have worked with directly.
Frequently asked questions
How many bore holes does a residential soil test actually need?
At least three, spread across the building footprint, plus a dedicated bore for a pool if one is part of the concept. A single bore only tells you the classification at that one point, not across the site.
Does a soil test tell me what my footings will cost?
Not directly, but it is the input that makes a real footing cost possible to estimate. Site classification, reactive soil depth and rock presence are the specific details a genuine cost position is built from.
Have your soil test results in hand?
A Foundation position turns those results into an actual cost picture.
Site conditions are one of the biggest cost drivers on a project — Foundation works from what you already have.