Symptoms of foundation problems

1. Stair step cracks in exterior walls

Stair step cracks in exterior walls usually indicate a longitudinal bending or flexing of the wall caused by the foundation settling. This can be caused by, vegetation in the fill under the footings (decaying trees, stumps, etc.).

2. Diagonal cracks in wall surfaces.

If the wall is an exterior wall, with the cracks from the corners of windows or doors. the problem is wall flexing as in #1.

If it's an interior wall, the problem is usually the slab is cracking and settling, or the footings and/or piers are settling, allowing the floor joists bend.

3. Sticking doors and/or windows. 

4. Some cracks are not a major problem requiring underpinning. For example horizontal cracks at the interface of the slab and the masonry wall (i.e. concrete block) due to the differing thermal expansion characteristics.

5. Older homes in areas with high chloride (salt) content in the soil can cause rusting and collapse of cast iron waste pipes. Over time a washout will occur causing settlement beneath the home's floor slab.