Building a Home: Soil Testing

The primary inspection that buyers of vacant land should perform after getting a contract is a soil test. Pipe clay, decaying organic matter and shallow ground water all pose a risk to the foundation of a home.

Daron marking the corners of the foundation.

Most soil testing companies will do four 10 foot borings as part of a standard residential soil test. Each of the four borings should fall within the footprint of the home that is yet to be built. After our initial builder consultation, we had a good working floor plan ready. It had been overlaid with a survey of the lot so we had accurate measurements of the foundation location. Daron (our builder) stepped off four corners and marked each with flourescent paint.

Next, we called a company to come out and test the soil. Using 10 foot augers, three technicians began boring holes on the four corners. Each handful of dirt that was removed from the ground was carefully scrutinized for any sign of trouble. A couple times they pulled what looked like clay from the dirt pile and each time my heart would stop.

Soil technician examining a boring sample.

Fortunately, nothing significant turned up in the test. There are solutions to fixing soil issues, ranging from reinforcing the foundation with additional rebar to excavating the site and back-filling it with workable soil.