How old were the houses? All houses get cracks over time simply due to shrinkage rates of different materials.
I've built a few homes in Kenwick and haven't had any issues. They've all been double brick on concrete too.
On a sloping clay site your biggest cost will be the siteworks and required engineering for the proposed load.
Those are the main reasons you switch from a concrete slab to a framed home. The savings can be $20-$40k in the hills.
Where are you thinking of building Reeco?
