Our building regs inspector has told us to use the following for out concrete floor
6 inches of hardcore, "then whacker it"
2 inches of sand "then whacker it"
Insulation (we have bought 100mm)
4 inch concrete
3 inches screed. (my husband says this sounds like too much screed though? is 3 inches right?)
How much can we expect the hardcore to compress?
What is the total depth we need to excavate?