Brisbane ground, and why the classification varies so much
Brisbane ground varies sharply across the city. Reactive clays through the western and southern suburbs regularly produce H1 and H2 classifications. Alluvial soils along the river and creek flats bring soft layers and shallow groundwater. Bayside lots run to sandier profiles, and the older established suburbs frequently turn up undocumented fill from earlier subdivision.
Older lots carry uncontrolled fill from previous builds, demolition material, filled gullies and mature trees that have been drying a reactive profile for decades. Any of those can push a lot to Class P, and none of them show up without a borehole.
What a soil test costs in Brisbane
Five things set the price.
A fixed-price package. Commissioned individually, this scope costs considerably more; bundling the fieldwork, laboratory testing and reporting into one mobilisation is what brings it down.
Send the site address, the lot and plan, and any drawings, and we come back with a fixed quote. If the ground turns out more complicated than the plans suggested, we ring you before doing anything that changes the price.
What we test for in Brisbane
Site classification, AS 2870
New homes, duplexes, townhouses, extensions with new footings and secondary dwellings.
Site classification, AS 2870
Geotechnical investigations, AS 1726
Retaining walls, hillside blocks, deep cuts, commercial buildings and civil works, acid sulfate, slope stability assessment, screw piling, contaminated land and proposed developments.
Geotechnical investigations
Wastewater and percolation testing, AS 1547
Site and soil evaluation, permeability testing and design loading rates for on-site wastewater systems, reported for council submission. Unsewered lots across the western and outer suburbs.
Wastewater and percolation testing
Who does the work
You ring, you get Luke Whittaker. Fourteen years in geotechnical work, twenty in construction, more than 10,000 site classifications and investigations across Queensland and New South Wales, and seven years supervising and consulting on more than 300 civil construction sites.
About Luke
Get a fixed quote
Send the site address, the lot and plan, and any drawings you have.
Common questions
A standard site classification is $880 including GST as a fixed-price package. Beyond that it depends on lot size, access, the number of test locations and whether laboratory reactivity testing is needed. Send the address and any plans and we will come back with a fixed quote, usually the same day.
On virtually every residential build, yes. Your certifier needs a site classification to AS 2870 before footing and slab design can be approved.
Yes. Uncontrolled fill from a previous build is a common reason a Brisbane lot classifies as Class P, and it is worth finding before the footing design is set.
Typically on site within 3 business days of booking, with the report issued within 2 business days of fieldwork. Laboratory shrink swell testing adds to that.
Often it is more than that. Slope, retaining and deep cut usually need a geotechnical investigation to AS 1726 as well as, or instead of, a residential classification. Send the plans and we will tell you which one covers you.
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