How Poor Drainage Leads to Sinking Concrete: Causes & Solutions

Concrete is built to last, but without proper drainage, even the strongest surfaces can sink, crack, and become hazardous. Water plays a major role in the erosion, shifting, and settlement of the soil beneath concrete, leading to costly damage if left unaddressed.

In this blog, we’ll explore why poor drainage is one of the biggest threats to concrete stability and provide solutions to prevent sinking and cracking before it happens.

How Water Causes Concrete to Sink

When water doesn’t drain properly, it seeps into the ground beneath concrete slabs, causing soil erosion, expansion, and instability. Here’s how it happens:

1. Soil Erosion Weakens the Base

When rainwater or irrigation runoff isn’t directed away from concrete surfaces, it washes away the supporting soil. Over time, voids form beneath driveways, sidewalks, and patios, leaving the concrete with no solid base—leading to sinking and cracks.

2. Expanding & Contracting Soil Causes Shifting

Different soil types react differently to moisture. Clay-heavy soil absorbs water, swells, and then contracts when dry, causing the ground to shift. This constant movement puts stress on the concrete, leading to uneven surfaces and cracks.

3. Water Pooling Leads to Structural Damage

If water pools in low areas, it can seep into existing cracks, causing further deterioration and soil instability. Freeze-thaw cycles in colder months make this even worse, as water expands inside the cracks, forcing them to widen.

How to Prevent Sinking Concrete with Proper Drainage

The good news is that drainage issues can be fixed before they cause serious damage. Here are key solutions to keep concrete stable:

1. Improve Gutter & Downspout Placement

Redirecting rainwater away from concrete surfaces is crucial. Make sure:

• Gutters are clean and functioning properly.

• Downspouts extend at least 5 feet away from concrete slabs.

• Splash blocks or underground drain extensions help disperse water safely.

2. Ensure Proper Grading & Sloping

Water should always flow away from concrete, not toward it.

• Ensure your yard has a slight slope away from walkways and driveways to prevent pooling.

• Adjust landscaping to guide water toward drains rather than allowing it to soak beneath concrete.

3. Install Drainage Solutions

If poor drainage is an issue, installing a French drain, channel drain, or catch basin can help collect and redirect excess water. These systems help protect the soil beneath your concrete, preventing erosion and shifting.

4. Fill Cracks & Seal Concrete

Small cracks let in moisture, leading to faster deterioration. Applying concrete sealant prevents water from penetrating and causing further damage.

What to Do If Your Concrete Is Already Sinking

If you’re noticing uneven surfaces, cracks, or water pooling, it’s important to act fast before the problem worsens. Concrete leveling can restore sunken slabs without the need for full replacement.

At Level Best Northwest, we specialize in concrete leveling and repair to keep your surfaces safe and long-lasting. If you’re dealing with sinking concrete, contact us today for a professional inspection.

Don’t let poor drainage ruin your concrete! Fix it before it becomes a bigger problem.

Contact us to get a free concrete inspection today!