The ground where you plan to build a home addition should be tested for several things that will determine whether a foundation can be built in the location and what type of foundation is most appropriate.

An engineer will need to determine what kind of soil is in the planned construction area. Some types of soil have a tendency to shift. Shifting will cause cracks in the foundation, walls, etc.

Engineers and workers will need to know the depth of the water table to know how deep they can dig for the foundation.

A Perc test will be done to determine how water drains through the soil. Drainage is a very important consideration both for the stability of the foundation and for the prevention of a build-up of dangerous mold.

The foundation will need to be built on undisturbed land, not fill dirt.

The engineer or the contractor will need to know if there are any underground lines or cables in the construction area (some might need to be moved).

Finally, a Radon Gas test will be necessary to protect your family.