PPI-BoreAid allows for two layers of soil.

Soil Thickness (T1) is the thickness of the first layer.

If T1 is greater than the depth of cover (H), then the pipe is completely contained in the first layer. Otherwise, there strata is defined by T1 feet of Soil Layer #1 and H-T1 feet of Soil Layer #2. For soil layer types, refer to the dropdown buttons embedded in the schematic diagram.