Soil, slope and site classification in Cobbitty
Much of western Sydney sits on clay soils weathered from the Wianamatta Group shales, and clay ground swells when wet and shrinks when dry. The site classification under AS 2870 is set lot by lot from a soil report, so we do not quote a single class for the whole suburb. What we see on Cobbitty sites is the practical side of that: ground not yet graded away from the slab at lock-up and fixing, and water left to sit beside the footings. Getting the fall right is one of the cheapest ways to protect a slab on reactive soil.
Western Sydney's clay soils largely derive from the Wianamatta Group shales.
AS 2870 site classes are set per lot from a geotechnical report.
Your soil report and slab engineering show the class that applies to your home.
Grading away from the house was outstanding on several Cobbitty jobs we inspected.
Sloping lots can need piers, retaining walls and careful stormwater design.
More about Cobbitty
- Building a new home in Cobbitty NSW 2570
- Buying a house in Cobbitty NSW
- Growth and new development in Cobbitty
- Approvals, certifiers and building disputes in Cobbitty
- Termite risk and protection for Cobbitty homes
- Common building defects in Cobbitty homes
- Bushfire, flood and wind considerations in Cobbitty
Written by our local inspection team from work carried out in Cobbitty. Licensed building practitioners, NSW Fair Trading licence 366177C.
