How to Fix a Sinking Patio Without Tearing It Out

You walk out onto your patio with your morning coffee, and you notice it. The table is tilting. There is a gap opening up between the concrete slab and the brick siding of your house. Or worse—during the last rainstorm, you saw water pooling right up against your foundation instead of draining away into the yard.

Your patio is sinking.

Panic sets in. You imagine jackhammers destroying your backyard oasis, heavy trucks tearing up your lawn, and a bill for $10,000 to pour a new patio. It is a nightmare scenario for any homeowner.

But stop right there. You almost certainly do not need to tear that patio out. The concrete itself is likely solid; it is the ground underneath that has failed. At Charlotte Concrete Repair, we specialize in "Concrete Lifting" and stabilization—techniques that can float that heavy slab back up to its original position in a matter of hours, for a fraction of the replacement cost.

The Mechanics of Sinking: Why Charlotte Slabs Drop

Before you fix the problem, you have to understand the enemy. In the Charlotte area, we fight two main adversaries: Red Clay and Poor Compaction.

1. The "Backfill" Trap

When your house was built, the builder dug a big hole for the foundation/basement. After the walls were poured, they pushed dirt back into the gap around the house. This is called "backfill."

Builders rarely compact this dirt perfectly. Over the next 5-10 years, gravity takes over. The dirt settles. If your patio was poured on top of this backfill zone (which it almost always is), the support simply vanishes. The heavy concrete slab crushes the air pockets out of the soil and drops.

2. The Clay Sponge Effect

North Carolina red clay acts like a sponge. It swells when wet and shrinks when dry. In dry summers, the soil actually retracts away from the bottom of your patio, leaving a void. In wet winters, it softens and turns to mush. This constant movement destabilizes the slab, causing it to tilt or crack.

3. Erosion and Washout

If your downspouts aren't piped far enough away, roof water might be washing out the dirt from under your patio. This creates large underground caverns. Eventually, the bridge collapses.

The Solution: Hydraulic Lift (Not Replacement)

So, how do we fix it without demolition? We use a process often called "Slab Jacking" or "Poly Lifting." The concept is simple mechanics, but the execution requires artistry.

Imagine your patio is a 4,000-pound boat sitting on a dry lakebed. To lift the boat, you don't need a crane; you just need to fill the lake. That is what we do with the soil voids.

Foam vs. Mud: Which is Better?

At Charlotte Concrete Repair, we are experts in the modern Polyurethane Foam method, though we understand traditional mudjacking. Here is why Foam wins for residential patios:

Weight: Traditional mudjacking grout is heavy (100 lbs per cubic foot). Pumping heavy mud onto soft soil can sometimes cause more sinking later. Poly foam is feather-light (4 lbs per cubic foot) but incredibly strong. It lifts the concrete without burdening the soil.

Waterproofing: Poly foam is hydrophobic. It cures in water. It forms a waterproof barrier under your slab that prevents future erosion. Mudjacking slurry can wash away just like dirt.

Appearance: Foam requires tiny 5/8" drill holes. Mudjacking requires large 2" holes that are ugly and hard to hide.

The "No-Tear-Out" Advantage

The benefits of lifting over replacing are overwhelming:

• Cost: Lifting typically costs 50% to 70% LESS than replacement. You are reusing your materials.
• Speed: A lift takes 2-4 hours. A replacement takes 3-5 days.
• Landscaping: We run a small hose to the patio. No bobcats tearing up your grass. No flower beds destroyed.
• Immediate Use: You can have a BBQ on your patio the same evening we lift it.

When Lifting WON'T Work

We value honesty. There are times when we must recommend replacement or sectional repair:

• If the concrete is shattered into dozens of small pieces (like a mosaic). We can't lift gravel.
• If the slab is structurally too thin (less than 2 inches) and will snap if we try to lift it.
• If the settling is due to a massive sinkhole or pipe collapse that requires excavation to fix safely.

However, for 90% of the sinking patios we see in Charlotte, lifting is the perfect, permanent solution.

Conclusion

Don't let a sinking patio threaten your home's foundation or your family's safety. And certainly don't pay to destroy a perfectly good slab of concrete. Contact Charlotte Concrete Repair today. We will assess your settlement, explain the science, and give you a quote to lift it back to perfection—saving your yard, your weekend, and your bank account.