3 Reasons Why You Have a Crumbling, Cracked Sidewalk

Most of us want to be proud of the way our homes look – something real estate professionals call “curb appeal.” It’s important because it impacts how we feel about our homes and neighborhoods. It’s especially vital when you’re thinking about selling your home. Few things can detract quicker from our curb appeal than a crumbling, cracked sidewalk.


“The concrete around our homes – like driveways, patios, and sidewalks – should enhance our quality of life. But when these areas crack, settle, and become uneven, suddenly you can be dealing with issues like pooling water, uneven surfaces, and dangerous trip hazards,” says Kraig Schjodt, a concrete professional at Thrasher Foundation Repair. And it just plain looks bad, especially when the surface begins to erode. 


When you have a sidewalk slab, decking around your pool or part of your driveway that is sinking or heaving, it can erode your peace of mind. The bad news is that it won’t go away on its own or get better with time. The good news is that once you understand the cause, you will find that there are faster, simple and less costly options that having new concrete poured.


Concrete is strong but brittle

Concrete is a versatile construction material. It is great at withstanding an enormous amount of weight. That’s why it’s used for foundations, driveways and sidewalks. Schjodt adds, “Concrete is pretty great stuff. It can be poured, shaped, and made into just about anything you like. But even though it’s incredibly strong, it’s not indestructible.”


Concrete is strong and durable, however, it also has a low tensile strength. Which is another way of saying it’s brittle. Concrete’s brittleness shows up when you put weight on it and there’s nothing underneath to support it. Many times, this causes the concrete to sink and become uneven.  


Cause #1: Soil beneath the slab is poorly compacted


Driveway cutaway showing void below concrete

A common reason for a crumbling, cracked sidewalk is poor soil conditions. Certain types of fill soil like clay absorb more water than other types of dirt. If the fill soil underneath your concrete isn’t compacted properly, it could absorb water and swell at different rates and shift beneath your concrete slabs.


“When your home was built, the contractor likely moved soil in, out, and around the building site. This fill dirt is often left poorly compacted,” says Schjodt. “And even when it is compacted well, it’s never as stable as the original soil.”


It’s a similar situation that can impact the stability of your foundation (read more here)


Settlement cracks occur when the soil beneath the concrete moves. And when the cracks multiply and grow, they can lead to other problems.


Cause #2: Soil beneath the slab is too dry


Cracked, damaged concrete slabs

During drought conditions or even just times of warm weather and low precipitation, the soil under your slab will dry out and shrink. That shrinking creates voids or spaces under your slab and reduces the support for the concrete. The concrete above eventually cracks and sinks into voids. Those gaps eventually lead to a crumbling, cracked sidewalk, driveway or patio. If the situation continues, you might be looking at replacing large areas of concrete.


Let’s talk for a minute about the good kinds of cracks. The intentional ones that are put into your slab of concrete, especially sidewalks and driveways, are called “control joints.” They are there to allow concrete to move and control the amount of potential cracking. But, if these joints aren’t properly sealed, that can be an access point for water.


Cause # 3: Soil beneath the slab is too wet


Broken, heaving sidewalk concrete slab

After periods of dryness, the rains eventually come back. Often, all at once. When the rain returns, that water has an even easier pathway under the slab due to cracks and crevices left behind from a drier time. The soil under your slab washes away or becomes too wet and soft to support the concrete above it. More washout. More wet, weak soil. More void.


Water can also swell clay-rich soil and the expansion can cause a sidewalk to heave, which stresses the concrete in an entirely different way. If you’ve walked your dog around the neighborhood at night and caught your toe on a slab of concrete that was sticking up higher than the one next to it, you likely have a few other choice names for it.


What is the best fix for a crumbling, cracked sidewalk


Concrete leveling using PolylevelConcrete joint sealing with NexusPro

The best way to combat these three causes of concrete erosion is to level it, then seal it.


Thrasher Foundation Repair offers a simple, quick and highly effective way to repair your sunken, cracked driveway, patio, pool deck or sidewalk. It’s called PolyLevel® polyurethane foam. PolyLevel is an incredibly strong, yet incredibly lightweight polyurethane material. That means it can lift and level your concrete without adding extra weight to the soil beneath. Better yet, it fills voids and compacts underlying soil, which stabilizes your concrete for years to come. Neither mudjacking nor concrete replacement can accomplish this.


After your concrete is lifted and leveled, then your cracked concrete and control joints are filled and sealed using NexusPro™ joint sealant. Schjodt says, “NexusPro seals the water out, greatly reducing the formation of damaging voids in the soil below. It simply won’t crack or de-bond over time and remains flexible in all temperatures.”


Do-it-yourself solutions don’t address the underlying problem

While surface problems can likely be patched, this won’t fix the underlying settlement problem and more cracks can form in your driveway or sidewalk. Do-it-yourself repairs might be less expensive, but they are messy, require special tools and equipment, and it can be as long as 30 days before you’re able to apply significant weight to it again (like your car, for example.) No matter what’s causing your driveway or sidewalk to sink, we can fix the problem fast and prevent further problems with our concrete repair solutions.


Returning your pride of ownership and peace of mind

If you don’t like what you’re seeing in the concrete surfaces around your home, give Thrasher a call. We can return your peace of mind by inspecting the problem and providing a detailed plan and estimate of how we can restore your concrete. And, sense of pride.


To help you decide what’s best for your home, Thrasher provides each of our customers with a free in-home inspection and same-day, no-obligation estimate in writing, before you spend a dime with us. Each estimate includes a detailed proposal on how we plan to fix your concrete problem and protect your home. Call us today at 800.827.0702 or fill out this short form to schedule an inspection.