What's in your site classification report
Every report we issue is built from field investigation and laboratory testing to Australian Standard methods, so your designer has measured data, not assumptions.
When a site classification is required
A site classification is required before footing and slab design on virtually every residential build in Queensland, and it is typically a condition of building approval.
If your site has cut and fill, established trees, uncontrolled fill or reactive clay, the classification is where those risks get identified, before they turn into a variation.
Understanding your site class
A more reactive class does not mean a difficult build. It means the footing system needs to suit the ground. The cost risk comes from finding out late, not from the classification itself.
What your classification means for footings and slabs
The site class is the input your designer needs to nominate a slab and footing system that will hold up over the life of the building.
On Class S and Class M lots, a conventional stiffened raft to AS 2870 is usually the answer, and the classification confirms the designer can use the deemed to comply tables in the Standard.
On Class H1, H2 and E lots the footing system has to carry more movement. That can mean a deeper edge beam, more reinforcement, a waffle raft, piers or a combination. Finding this out at design stage costs less than finding it out after approval.
On Class P lots there is no deemed to comply solution. Uncontrolled fill, soft or compressible soil, significant slope, erosion or an abnormal moisture condition means the footing system has to be engineered for that specific condition. A Class P result means somebody has to design for it, instead of assuming the neighbouring lot is a guide.
Our report gives your designer the reactivity data, the site constraints and practical foundation, site preparation and drainage recommendations they can work from. Where a project needs the full footing and slab design as well as the classification, we engage our structural engineer and scope both in the one job.
Testing to Australian Standard methods
Reactivity cannot be judged by eye. Where a reactive profile is present, we test to the AS 1289 series:
Results are combined with the design depth of suction change for your climatic zone to calculate characteristic surface movement under AS 2870 Appendix D. That number determines your site class, and it is stated in the report, not hidden behind it.
Laboratory testing runs through NATA accredited facilities.
Where we work
Brisbane, Moreton Bay and the Sunshine Coast, plus Ipswich, the Gold Coast and Northern New South Wales.
Soil testing, Moreton Bay
Soil testing, Brisbane
Common questions
We typically mobilise to site within 3 business days of your booking, with the report issued within 2 business days of fieldwork being completed. Where laboratory shrink swell testing is required, allow additional time for the testing turnaround. If your programme is tight, tell us early and we will work to it.
On virtually every residential build in Queensland, yes. Your building certifier needs a site classification to AS 2870 before footing and slab design can be approved, and the classification is normally a condition of the building approval. Get it done before drawings are locked in. A reactive result changes the footing design, and designing for it costs less than redesigning around it.
For a standard house on a conventional lot, an AS 2870 classification is usually the right scope. Retaining walls, steep sites, deep cuts, commercial buildings and civil works generally need a broader investigation to AS 1726. If you are unsure, send us the plans and we will tell you which you need. More on AS 1726 geotechnical investigations
Cost depends on lot size, access, the number of test locations required and whether laboratory reactivity testing is needed. Send through the site address and any plans you have and we will come back with a fixed quote.
Site address, lot and plan details, and a site or architectural plan if you have one. Proposed levels and any known fill or demolition history help us scope the investigation accurately.
Yes. Mature trees draw moisture from reactive soil, and removing them lets the soil re-wet and heave, sometimes over many years. Tree location, species and whether they are being retained or removed can change the classification and the footing advice.
Get a fixed quote
Send the site address, the lot and plan, and any drawings you have.
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