Most concrete cracking and settling isn't caused by the concrete itself — it's caused by water that was never routed away from it in the first place. Here's how downspouts and poor drainage wear down a driveway or patio over time, and what fixes actually address the cause instead of just the crack.
How water undermines concrete
Concrete slabs sit on compacted soil, and that soil is what actually holds the slab up. When a downspout dumps water right at the edge of a driveway or patio instead of carrying it further away, that soil saturates, erodes, and eventually washes out from underneath the slab. Once the base is compromised, the concrete above it has nothing solid to rest on — that's when you start seeing settling, sinking corners, and cracks that keep coming back after they're patched.
Warning signs to watch for
- Pooling water that sits near a slab edge for hours after rain instead of draining away.
- A visible gap or step where one section of concrete has settled lower than the section next to it.
- Erosion channels or bare soil runs leading from a downspout toward the driveway or patio.
- Cracks that reopen in the same spot after being patched, which usually means the underlying base issue was never fixed.
Fixes that actually solve the problem
Downspout extensions carry water several feet further from the foundation and slab edge — often the simplest, cheapest fix available. For yards with persistent pooling, a french drain or buried drain line can redirect water underground to a lower point on the property. Regrading a small area near a slab edge can also restore the slight slope needed to carry water away instead of toward the house.
Why fall is the right time to address it
Fixing drainage issues before winter matters because saturated soil that freezes and thaws repeatedly causes far more damage than saturated soil in warmer months. Addressing a drainage problem in October or November prevents it from turning into a much bigger concrete repair by spring.
We handle both drainage fixes and concrete repair across the St. Louis metro. Get a free assessment and we'll tell you honestly whether it's a drainage issue, a concrete issue, or both.