How Does Water Cause Foundation Cracks to Spread?

When water finds its way into a foundation crack, it does not just sit there. The water carries fine soil particles with it as it moves, slowly washing out the ground underneath the concrete. That leaves small voids, and the foundation loses support in those spots.

At the same time, the water itself puts pressure on the crack walls. In cold climates with freezing winters, that water often freezes. Ice takes up more space than liquid water, so it pushes outward against the concrete with considerable force.

Water also changes the soil that supports the foundation. When the ground gets very wet, the soil becomes soft and compressible. The foundation sinks a little in those spots. When the soil dries out, it can shrink and pull away, leaving gaps under the concrete.

This uneven movement puts new stress on the foundation. One part of the slab or wall may settle while another part stays put. The resulting twist and bend can widen existing cracks and create new ones along the weakest points.

If you notice a foundation crack getting worse, act quickly. Start by redirecting water away from the foundation with gutters, downspout extensions, and proper grading. Fix any leaking pipes or sprinklers that keep the soil wet next to the house.

For the crack itself, a local water damage pro can inspect the foundation and recommend the right repair. The work usually involves stabilizing the soil, sealing the crack, or both. The cost depends on the crack size and the cause, so get a clear plan before starting.