Concrete is one of the toughest, most heavily used construction materials in existence, but it doesn’t come without issues. Patios in particular tend to go uneven over time. An uneven concrete patio isn’t just unsightly. It creates a trip-and-fall hazard, and in bad cases a cave-in over a hidden void can cause real injury. We’ve leveled thousands of Colorado slabs since 1988, so here’s an honest look at your options, including the ones that don’t involve calling us.
Several factors contribute to an uneven concrete patio, including:
- Improper pouring technique during installation
- Soil shifting underneath the concrete
- Natural wear and tear from extreme weather
Soil is the usual offender around Denver. Erosion and our expansive clay work on outdoor slabs year after year, and poor soil compaction before the original pour speeds up the timeline. Shifting soil opens voids beneath the patio, and voids lead to bigger, more dangerous problems, so address the movement as soon as you notice it. Weather does its part too: freeze-thaw cycles, spring runoff and baking summer sun all push and pull on a slab until sections start to drop.
Whatever the cause, fix the problem before it gets worse. A professional concrete raising company is often the best route, but for those determined to do the project themselves, here are the main methods.
Method 1: Concrete Leveling Compound
For patios that are only slightly uneven, a concrete leveling compound is often enough to re-level the surface. Start with a thorough cleaning, using a pressure washer or a commercial concrete cleaner, then grind away the top layer of concrete to give the bonding agent a rough surface to grip.
Next, build a form around the downward-sloping area using 2x4 or 2x6 lumber so the compound can’t flow outside the patio. Badly sloped patios may need to be fully enclosed. Once the slab is free of dust and debris, apply the bonding agent, then mix and pour the leveling compound starting at the low end. A metal trowel helps you feather the surface flush. After the material dries, typically overnight, remove the boards.
Understand what this method does and doesn’t do: it resurfaces the top of the slab, but it adds weight without filling the void underneath. If soil movement caused the low spot, the settling usually continues.
Method 2: Cut Out and Replace the Problem Section
Sometimes only one section of the patio needs attention. In those cases it may be practical to remove just the affected piece with a jackhammer or concrete cutter. DIYers beware: these are dangerous tools, and rental counters won’t teach you technique.
Once the problem area is out, add material (often sand) to bring the base up to the proper height, then compact it with a tamping machine to prevent future sinking. Pour or set a new piece of concrete cut to size, fill the joints with additional concrete or a patching compound, and let everything dry overnight.
Method 3: Call a Professional Concrete Raising Company
Professional crews level slabs using either polyurethane foam or mudjacking, which pumps a slurry mixture beneath the slab to raise it. Polyurethane foam is marketed as the more modern option and some contractors prefer it, but it doesn’t always completely fill the space under the slab, and polyfoam can contain harmful chemicals. Mudjacking uses a natural soil-and-cement slurry that fills voids solidly and compacts the base as it lifts.
DIY or Pro? How to Decide
Here’s the quick test we give homeowners over the phone. Leveling compound suits you if the surface is structurally sound, the dip is shallow, and the cause was a sloppy pour rather than moving soil. Cutting out a section makes sense if damage is isolated and you’re comfortable running serious tools. Call a pro when the slab has dropped an inch or more, when a corner sounds hollow underfoot, when the patio tilts toward your foundation, or when the same spot keeps sinking after a repair. Those symptoms point to voids and soil problems that surface fixes can’t reach.
Budget belongs in the math as well. DIY materials look cheap until you add tool rentals, a weekend or two of labor, and the real chance of paying someone to redo it. Raising a slab costs a fraction of replacing it, and once the patio sits level again you can put the savings toward the fun part. Our roundup of concrete patio ideas on a budget is a good place to start.
What the Pros Do Differently
The visible work, drilling small holes and pumping slurry, is the easy half of the job. The judgment is the hard half. An experienced crew figures out why the slab moved before lifting it, so the fix addresses drainage or soil problems instead of papering over them. During the lift, we monitor pressure and raise the slab gradually across multiple points; lifting too fast or in the wrong spot cracks the very concrete you’re trying to save. And because the slurry fills the entire void, the slab gets uniform support instead of resting on a few high points.
When the time comes for your patio to be re-leveled, your best bet is to leave it to the pros. AAA Concrete Raising has provided mudjacking services in Colorado since 1988, and we run one of the biggest sandy loam soil trucks in the industry, so we carry enough slurry for even the largest concrete raising jobs.
To learn more about our mudjacking services and get a free estimate, contact us or call (303) 526-2222 today.
