Discovering sinking areas within your property can be distressing. Besides negatively impacting the appearance of your home, uneven concrete surfaces can cause tripping hazards and reduce your property’s value.
Fortunately, getting a replacement isn’t the only solution to this problem. You don’t necessarily have to spend a fortune or endure the disruptive concrete work that often comes with hiring demolition and installation services. Learning how to lift a concrete slab gives you a quick and cost-effective way to get your concrete driveway or walkway back to normal.
Before moving on to the intricacies of concrete lifting, let’s take a step back and understand why concrete sinks in the first place.
Why Does Concrete Sink?
Various factors can cause concrete to sink, but most are related to problems with the base supporting it. Concrete is durable but also significantly heavy, so the soil underneath it must be able to support its weight. Otherwise, the slab will sink or crack.
Professionals use compacted materials like sand, gravel, or cement when pouring concrete as a substrate. This provides the concrete with stable and even support. Without proper compaction during construction, the soil can settle down over time and leave behind voids that reduce the support for the concrete. This makes the slabs prone to sinking or cracking.
Pooling rainwater or leaky underground pipes can also contribute to concrete sinking. Water that gathers around the edges of the concrete slab or soaks the substrate can quickly erode it – and the support it provides. When this happens, slabs sink or fracture under their own weight.
Regardless of the cause, it’s crucial to correct the issue that caused the sinking first. Otherwise, the problem will return, and your efforts to lift your slabs back to a normal level will be in vain.
How To Lift a Concrete Slab
Concrete lifting, also called concrete leveling, is a quick and hassle-free method of stabilizing concrete. Many methods can be used to raise slabs, but here are the general steps when lifting concrete using a slab jacking pump.
Step 1: Drill Dime-Sized Holes
The lifting process starts with drilling dime-sized holes into the sunken slabs. These must be around three to eight feet apart but at least one foot from the slab’s edge. Also, the general rule is that the thicker the concrete, the farther apart these holes can be. Still, these holes will serve as the entryway for the lifting solution, so they must be at approximately equal distances from one another.
If you are learning how to lift precast concrete steps, sometimes a special sidewalk jack works better than drilling holes.
Step 2: Install the Delivery Port
Once the holes are ready, install tapered delivery ports into them. These ports will be connected to the application gun, which will be responsible for transporting the lifting material to the voids underneath the sunken slab.
Step 3: Pump the Lifting Material
Once the delivery ports are inserted and ready to be used, it’s time to start pumping the lifting material and filling the void in the substrate. For best results, it’s recommended that you begin at the lowest part of the recessed surface.
What Kind of Foam Is Used To Lift Concrete?
Today, many concrete professionals use polyurethane foam or polyfoam to lift concrete slabs. This fast-acting material only requires smaller holes and fewer injections. This lifting solution is even more advantageous because it can fill voids and stabilize concrete within seconds while staying lighter than sand or cement.
Besides polyurethane foam, traditional concrete leveling methods use a mixture of water, soil, sand, and cement in a process called mudjacking. This mortar-based mix is pumped underneath a cracked or sunken concrete to lift slabs upwards.
Step 4: Monitor the Raising
Concrete leveling is best done with incremental injections. For example, as polyurethane foam expands after it is injected, it slowly compacts the soil underneath and pushes the slabs upward. This vertical movement must be monitored closely before making further injections.
If necessary, you can also alternate the points of injection used to balance the pressure put on the substrate – and ensure the slabs rise to a level position. Even and steady lifting helps keep concrete from cracking throughout the process and provides satisfying results.
Step 5: Patch the Holes
Once you’re satisfied with the elevation of your previously sunken slabs, it’s time to close the holes. Remove the delivery port and seal the holes using a mortar mix. For a smooth and seamless finish, it’s best to apply the mixture carefully.
Hire Professional Concrete Lifting and Use Your Pavement Without Worry Again
Raising concrete slabs is faster, simpler, and more cost effective than getting a replacement. It also allows you to use the treated driveway, walkway, or steps soon after the lifting material has expanded to minimize disruption. As such, we hope this blog on how to lift a concrete slab gave you ideas to maximize this practical solution.
If you’re dealing with a special project or want to ensure the best results, it’s better to entrust your sunken concrete to the professionals. You may think that taking the DIY route can save you more cash. However, it can cost you more in the long run, especially when you discover an issue with your work and have to repair it again. Professionals will have the expertise and equipment to get the job done right the first time and ensure your concrete surfaces look good as new from the outside.
At The Driveway Company, we have experts trained and experienced in concrete lifting. Our years in this line of work also helped us gain extensive knowledge of soil conditions in the area – something we take advantage of to raise concrete slabs successfully. The best part? We meticulously hand-tool our commercial-grade products into your concrete’s problem areas for a smooth and seamless finish.
If you’re troubled by sinking slabs within your property, book a free inspection today. We look forward to making your concrete surfaces an enjoyable and worry-free space for you again.
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