Houses in West Australia are built on a concrete slab that is installed on heavily compacted sand. They guy who laid the slab screwed up, and for some reason the brickie followed the slab despite using around 6sqm more bricks than he should have used. It wasn't till the roofies came that the mistake was picked up. Due to planning regs, the walls had to be shortened and the slab had to be cut back by one lineal metre. Fortunately there was no plumbing involved.