Digging the Foundation Hole

Nothing is as simple as it seems. About a third of the way into digging the hole for the new foundation, I got a call from the trackhoe operator. He informed me that he was concerned about the soil he was finding below the surface.

He kept digging and I called an engineer to inspect the soil. That afternoon the engineer called back and said we had a foundation hole full of "shale". Shale is a type of expansive soil, meaning that it expands and contracts with varying moisture levels. This is not good for a foundation to sit on!

The solution: excavate an additional three feet and replace the poor soil with compacted limestone or recycled concrete fill. Not an inexpensive venture!

This is a picture of the foundation hole before the extra work.

While I was trying to get the fill work lined up, one of the side walls fell into the hole. Nobody was hurt, but I had to get the trackhoe operator back out to pull all the fallen dirt back out of the foundation. Cost: more money and another day of work gone!