A concrete slab can sink for a variety of reasons, but there are some things you can do to fix the problem yourself. This blog post will show you how.
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Assess the damage to your concrete slab.
Before you begin, it’s important to assess the damage to your concrete slab. If the sunken area is small and not causing any problems, you may not need to do anything. However, if the sunken area is large or causing problems such as trip hazards or water pooling, you will need to take action to fix it.
There are two main ways to fix a sinking concrete slab: mudjacking and polyurethane injections. Mudjacking is the more traditional method and involves pumping a slurry of mud and water under the slab to raise it back into place. Polyurethane injections are a newer method that involves injecting a foam-like material under the slab to fill voids and raise it back into place.
Both methods are effective, but each has its own advantages and disadvantages. Mudjacking is generally less expensive, but it can be messy and disruptive. Polyurethane injections are more expensive, but they are less messy and disruptive. Ultimately, the best method for your situation will depend on your specific needs and budget.
Dig out the affected area around the concrete slab.
It’s important to excavate the area around the slab so you can get to the root of the problem. The depth of excavation will vary depending on the severity of the sinking and the stability of the soil. In most cases, you’ll need to excavate around 2 feet (60 cm) around the perimeter of the slab.
If the soil is very soft or unstable, you may need to excavate even deeper. Be sure to check for underground utilities before you start digging! Use a shovel or an excavator to remove any loose soil from around the slab. Once you’ve excavated the area, you can begin to assess the damage and decide on a course of action.
Pour a new concrete footing around the perimeter of the slab.
If you have a sinking concrete slab, it’s important to fix it right away. Otherwise, you’ll end up with an uneven surface that’s difficult to walk on and an eyesore in your yard.
The best way to fix a sinking concrete slab is to pour a new concrete footing around the perimeter of the slab. This will provide support for the sides of the slab and prevent it from sinking any further.
You’ll need to excavate around the perimeter of the slab to a depth of about 8 inches. Then, you’ll need to pour a new concrete footing that is at least 6 inches thick. Once the footing has cured, you can then pour a new concrete slab on top of it.
Reinforce the new concrete footing with steel mesh.
Once you’ve poured the new concrete footing, it’s important to reinforce it with steel mesh to help prevent future cracking. To do this, simply lay the steel mesh on top of the wet concrete and make sure that it’s completely covered. Once the concrete has cured, you can then add your slab on top of the new footing.
Pour new concrete over the footing and finish it off.
If your slab has settled only a few inches, you might be able to pump in a specialized concrete grout through small holes drilled in the slab to fill the void and raise it back to level. This is called mudjacking, and it costs about $500 for a typical 10- by 10-foot patio.
But if the foundation has sunk more than a few inches or one corner has dropped below the level of the finished surface, you probably have no choice but to jack up that corner, excavate around the footing, pour new concrete and finish it off. That’s called mudjacking, and it costs about $500 for a typical 10- by 10-foot patio.