When building slab foundations, the concrete pour comes after the footings have set and before walls are erected. Dirt is compacted and backfilled with 4 to 6 inches of gravel.

After removing the soil, tamp down the base of the trench to create a sturdy foundation. To keep the curve consistent while ...

A footing trench ranges from six inches to three feet deep, depending on the building size and soil characteristics. ... Reinforced Block and Concrete Walls. Block foundations use cinder blocks ...