Site Classification under AS 2870 – Is the Cheapest Investigation Really the Cheapest Option?

Site classification in accordance with AS 2870 plays a critical role in footing design, construction cost, and long-term performance of residential projects.

While the Standard allows visual–tactile assessment by a qualified geotechnical professional, relying solely on limited data can result in conservative site classifications and more expensive foundation systems.

Laboratory testing (e.g. shrink-swell index testing) provides a more accurate assessment of soil reactivity and characteristic surface movement (ys), which can lead to more optimised and cost-effective footing design.

In practice, the cheapest investigation does not always mean the lowest overall project cost. Overly conservative classifications can result in deeper beams, heavier reinforcement, and higher construction costs.

At Torrens Geotechnics, an experienced geotechnical engineer attends every drilling site to ensure accurate soil logging, appropriate sampling, and high-quality data collection for reliable AS 2870 site classification.

For landowners, developers, structural and civil engineers, a well-planned geotechnical investigation reduces risk, improves design efficiency, and helps avoid costly variations during construction.

Whether you’re planning a new home, townhouse, commercial building, or extension, Torrens Geotechnics helps you start your project with clarity and confidence.

Request your free quote today and make sure your project starts on the right footing.