Ground conditions and slabs in Gables NSW
The north west growth area sits on the Cumberland Plain, where weathered shale generally produces clay soils that swell when wet and shrink when dry. Slabs are designed to ride out that movement through beam depth, reinforcement and cover, and on sloping Gables lots through stepped slabs with extra reinforcement at each step. We do not publish one site class for the suburb, because AS 2870 classification belongs to each lot and its soil report.
Clay that moves
Clay soils change volume with moisture across the seasons. Some movement and fine cracking is normal; widening or patterned cracking is not.
Site class is per lot
Your site class comes from your lot's soil report. Two lots in the same street can differ.
Stepped slabs
Where a lot slopes the slab may step down. The engineering calls for reinforcement carried past each step, and we have found it missing on a Gables pour.
Cover and mesh height
A slab's stiffness depends on its steel being where the engineer put it, so cover and mesh height are the core of a pre-pour check.
Keep water away
After handover, keep the ground falling away from the slab and stormwater discharging into the system, not beside the footing.
More about Gables
- Building a new home in Gables NSW
- Buying a home in Gables NSW
- Growth and development in Gables NSW
- Certifiers, council and building disputes in Gables NSW
- Termite risk in Gables NSW
- Common building defects in Gables NSW
- Bushfire, flooding and wind in Gables NSW
Written by our local inspection team from work carried out in Gables. Licensed building practitioners, NSW Fair Trading licence 366177C.
