A Slab Is Only as Good as What It's Engineered For
A shed slab and a granny flat slab might look similar once poured, but the engineering behind them is very different — a habitable structure typically needs a slab designed to a soil report and engineering specification, with reinforcement, thickness and edge beams sized accordingly. A garden shed slab has much lighter requirements. Getting this wrong in either direction either wastes money on unnecessary specification or creates a genuine structural risk.
We work from your soil report and engineering drawings where they exist, and can point you toward getting one prepared where a project needs it. For simpler structures like sheds and carports, we specify based on the structure's actual weight and footprint rather than a generic slab thickness.
Adelaide's Soil Classifications and Slab Design
Much of the Adelaide metro area is classified as reactive clay (Class M or Class H sites under the relevant Australian Standard), meaning the soil moves more than average with seasonal wet and dry cycles. This directly affects how a slab needs to be designed — from a simple raft slab through to a more heavily engineered footing system on the most reactive sites. We factor your specific site's classification into slab design, and won't apply a standard-issue spec to a site that clearly needs more.