Watch Out for Washout: The Hidden Threat Under Your Concrete

 

What Is Washout?

Concrete is only as stable as the soil underneath it. Every driveway, sidewalk, porch, and pool deck relies on the ground beneath it for support. When water repeatedly flows under or against that concrete, it slowly carries the soil away, grain by grain, until a void, or empty pocket, forms beneath the slab.

That's washout. The concrete looks fine on top, but underneath, the support it was poured on is literally being washed out from under it.

Once that void gets big enough, the unsupported concrete has nowhere to go but down. That's when you get the cracking, sinking, and settling that most homeowners eventually notice.

Why Louisiana Homes Are Especially Vulnerable

We deal with a perfect storm of conditions for washout in southern Louisiana:

• Heavy, frequent rainfall. We get a lot of water, and we get it fast. Sudden downpours send large volumes of water rushing across and under concrete surfaces.
• Expansive clay soils. Much of our region sits on clay that swells when wet and shrinks when dry. That constant movement creates gaps and channels for water to travel through.
• A high water table. Groundwater sits close to the surface here, which keeps soil saturated and easier to erode.
• Tropical weather and flooding. Hurricane season and heavy storm events can move an incredible amount of soil in a very short time.

Put those together, and it's easy to see why washout is such a persistent issue for local homeowners.

Common Causes of Washout

Rain gets most of the blame, but washout usually has a specific culprit funneling water where it shouldn't go. The usual suspects include:

• Downspouts that dump roof water right next to a slab instead of carrying it away
• Poor drainage or grading that lets water pool against concrete
• Gutters that overflow or discharge in the wrong spot
• Plumbing or irrigation leaks slowly saturating the soil below
• Missing or damaged expansion joints that let water seep between slabs

Warning Signs to Watch For

You don't have to wait for a slab to collapse to catch washout early. Keep an eye out for:

• Concrete that's sinking, settling, or sitting unevenly
• Cracks appearing across driveways, walkways, or patios
• Gaps opening up between the slab and the soil beside it
• Concrete that sounds hollow when you tap or walk on it
• Water that consistently pools in the same spots after rain
• Visible voids or erosion channels along the edges of your concrete

That last one is the clearest signal of all. If you can see open space underneath your slab  (like the washout in the photo that inspired this post) the soil support is already gone, and it's time to act.

Why You Shouldn't Wait

Washout doesn't fix itself, and it rarely stays small. An unsupported slab keeps settling, cracks keep spreading, and what starts as a cosmetic annoyance can become a genuine safety hazard; a tripping risk on a sidewalk, a low spot that traps even more water, or damage that eventually threatens your foundation.

The good news: the earlier washout is caught, the simpler and more affordable it is to correct. A small void is far easier to fill than a fully collapsed slab is to replace.

How Frontline Fixes Washout

At Frontline Concrete Solutions, we don't just patch the surface, we address the empty space underneath. Using polyurethane foam injection, we fill the voids left behind by washout, stabilize the soil, and lift settled concrete back to its proper position. The foam expands to fill every gap, cures quickly, and provides durable, long-lasting support without the mess, downtime, or cost of tearing out and repouring your concrete.

And because we know washout is really a water problem at its core, we'll also help you identify the drainage and runoff issues causing it in the first place, so the fix actually lasts.

Don't Let Washout Undermine Your Home

Washout is sneaky, but it's very fixable when you catch it in time. If you've spotted any of the warning signs above (or you just want peace of mind before the next big storm), we're here to help.

Frontline Concrete Solutions is a veteran-owned company proudly serving all of sourthern Louisiana. Reach out today to schedule your inspection, and let's keep your concrete standing on solid ground.