Post date: Apr 11, 2015 2:26:15 PM
Now that the hole is dug — and we removed a dozen 12-cubic-yard truckloads of dirt to our landscaper’s yard — we start filling the hole.In addition to the material from the parking pad, which we had stored across the road, we bought 14 truckloads of ‘pit run’ (rock plus gravel plus sand) and laid this down in layers in the hole. Each layer was compacted with a vibrating roller to a total depth of 24”, with special attention around the edges, which will support the foundation footings.
During the compaction the wall of the hole that consisted of rock and sand (as opposed to silt and clay — see photo) collapsed. Fortunately I had warned the worker who was not protected by a big machine, so he was constantly aware of the potential for collapse. But it meant we had to remove more material than planned, since a big pile of dirt was atop this loose material.
We marked the width of the footings away from the walls of the hole and filled an additional six inches (also compacted) to support the slab. Since the footings must be below the frost line (30” below grade) this meant a deep hole, all to be filled with purchased material of one sort or another.