Cracks in the foundation can cause a number of problems. They can bring floors out of level and become a path for water, rodents, and insects to infiltrate the home. If the foundation is not stabilized, it can cause windows to crack and doors to not close properly. You might see damage to drywall and gaps or breaks in trim work. Foundation cracks, when severe, can lead to catastrophic structural failure in a seismic or high-wind event.