Expert
Don't DIY if you don't know what you're doing.
4 hours
Large projects with lots of concrete will take a few more hours.
Cost
$500–$1,000
Consider letting a pro with all the equipment handle this one.
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What you'll need:
TOOLS
- Circular saw with diamond blade (optional)
- Hammer drill with diamond drill bit
- Hydraulic slurry pump
SUPPLIES
- Gloves
- Safety glasses
- Face mask
- Marking tape
- Slurry mix (optional)
- Concrete patching compound
- Concrete repair caulk
Over time, concrete used for patios, walkways, stairs, and even foundations can sink into the ground. This happens for a number of reasons, including ground pressure, movement and settling, and poor drainage. If you have noticed your concrete steps no longer line up with a door or your concrete patio slab is a few inches lower than it used to be, you can raise the concrete with DIY mudjacking.
What Is Mudjacking?
Also known as concrete lifting or slabjacking, mudjacking is a technique used to raise sunken concrete slabs. The process injects a slurry of concrete below the slab to provide support and lift it to its proper level. Not only does this help you save on the cost of concrete removal, but you also don't waste the cost of the concrete slab you invested in the first place.
This guide will walk you through step-by-step DIY mudjacking or the concrete lifting process, so your concrete sidewalk, patio, driveway, or deck can get back to the right level. And if you’re looking to mudjack a foundation or other structural concrete, leave this task to a professional mudjacking contractor.
Prepping to DIY Mudjack
Mudjacking requires the use of heavy-duty power tools. When using power tools, always wear gloves for hand protection and safety glasses for eye protection. You should wear a face mask while cutting or drilling into concrete, so you are not inhaling the concrete dust.
Finally, because the process involves building up pressure beneath a concrete slab, always stay alert and be aware of your surroundings while mudjacking the slab to avoid injuries from the rising concrete.
Determine the Desired Concrete Elevation
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Before getting started with mudjacking, be sure you know the desired height for your concrete slab. If you are raising a section of sidewalk or driveway, you will, of course, want the sunken concrete to be level with the other sections.
If you are raising an entire concrete patio slab or a set of stairs, however, it is a good idea to mark the desired height of the concrete on your home’s foundation with marking tape. This way you will know when the slab has reached the desired height and won’t raise the concrete too high or not enough.
Cut the Concrete Slab, If Necessary
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If you only need to raise a section of a concrete sidewalk or driveway, you will need to separate it from any nearby sections. Use a circular saw with a diamond blade to cut the concrete at an existing joint. Be sure to fully cut through the concrete, so the slab you will be raising is separated.
Drill Injection Holes Into Concrete Slab
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To raise your concrete slab, you will be injecting a slurry mixture beneath the slab that raises it up. First, you need to drill injection holes into the slab for the slurry mixture. Using a hammer drill and a diamond drill bit, drill several holes across the surface and all the way through the concrete slab.
If you just need to raise the corner of a slab, drill one or two holes in that particular corner. If you need to raise an entire slab, drill a hole in each corner and a few others across the slab so the slurry mixture can fill in everywhere beneath the concrete, usually every 3 feet or so. Be sure your drilled holes go all the way through the slab and into the dirt or stone below and are about 1-5/8 to 2 inches in diameter.
Mix or Order Mudjacking Cement Slurry
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Next, you will need to mix or order a mudjacking cement slurry. The slurry is typically made with a combination of water and sand, clay, or topsoil, and limestone dust, or portland cement. This mixture can be ordered from a local concrete supplier or mixed at your property if you have the correct materials available.
Once the cement slurry is available, it should be transferred to a hydraulic slurry pump that will be used to inject the slurry into the concrete.
Pump Slurry Into Injection Holes
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Using the hydraulic slurry pump and the attached nozzle, pump the slurry mixture into each one of the injection holes. Start injecting the mixture at one side of the concrete slab and slowly move to the other side. Fill each hole until the concrete slab begins to lift to the desired height. Some holes may require more slurry mixture than others to fill the voids beneath.
Be sure not to overfill any of the voids, causing the concrete to lift past the desired elevation. Additionally, do not create a significant elevation difference from one side of the slab to the other. This can cause the concrete to crack. It is best to fill slowly and come back to an injection hole later if more material is needed.
Check Concrete Elevation and Continue Pumping, If Needed
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Once every injection hole has been filled with the slurry mixture, take a step back and evaluate the slab. Determine if the slab has reached your desired elevation and if the slab is level. If the slab is still too low or if certain areas need to be raised further, continue pumping the mixture into those specific injection holes.
Fill Cracks and Injection Holes
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Once your concrete slab reaches the desired height, you can stop pumping in the slurry and rinse down the entire surface gently with a hose. Patch the injection holes and any concrete cracks with a concrete patching compound or repair caulk.
Wait for the Slurry to Dry
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With the mudjacking process finished, the material beneath the slab needs to dry. It is typically acceptable to walk on the slab right after the material has been installed, but avoid placing any heavy objects on the slab for 24 to 72 hours.
DIY Mudjacking vs. Hiring a Pro
Mudjacking a concrete slab is a highly complex DIY project that will ultimately cost between $1 and $5 per square foot. That being said, this price does not account for all the related tools and the possibility you'll need to pay for repairs should something go wrong.
You will likely need to rent all the equipment for the job, which includes a concrete circular saw, hammer drill, and a hydraulic slurry pump. Renting these tools and purchasing the necessary supplies could cost anywhere from $100 to $500. You’ll also need to consider the cost of the concrete slurry (you’ll save money if you mix your own instead of buying it from a concrete supplier, though).
If you don’t already have the required tools for this project or you’ve never worked with a concrete mixture, leave this task to the professionals. The cost of mudjacking while hiring a professional is anywhere from $3 to $6 per square foot. While the project may end up costing a bit more, a local concrete mudjacking contractor will make sure your concrete slab is raised to your desired height, completely level, and does not crack during the process.
Lastly, it's crucial to check with local building codes before attempting mudjacking on your own. If the area falls into a right-of-walk sidewalk or your state has strict DIY construction laws, you may be required to call a pro for such a large project.
Tips for Preventing Your Concrete Slab From Sinking
There are several factors that can send your concrete sinking into the ground like the house in “Poltergeist.” Poor installation, drainage issues, tree roots, or ignored decay can all lead to losing structure support. Here are seven tips for keeping the slab above ground:
Ensure proper concrete mixing when installing the slab. The wrong concentration of water or an incorrect curing time can lead to structural issues. And remember, cement versus concrete is easy to confuse for one another.
Install a proper subbase of sand or aggregate below your concrete slab for support. The subgrade (the compacted soil below your subbase) should also be level and strong.
Test your soil composition before installing a concrete slab.
Address potential drainage issues, particularly when water pools on or around the slab.
Fortify large cracks or the space between slabs with backer rods and polymeric sand.
Repair concrete cracks as soon as they appear to keep the slab from sinking on one side.
Address impeding tree roots that could shift the slab over time.
Brionna Farney contributed to this piece.
Frequently Asked Questions
Polyurethane foam and other similar aggregate slurries provide concrete leveling alternatives to mudjacking. While the processes are similar, they may be easier than mudjacking because other materials may be easier to inject below the concrete slab, requiring less disruption to the area. However, keep in mind that mudjacking alternatives may cost more upfront.
Mudjacking uses a concrete slurry, while polyjacking uses a polyurethane foam to raise a sinking concrete slab. Both approaches inject the mixture through holes to lift up the slab, but polyjacking will cure more quickly and it is more lightweight than the slurry. Some contractors also prefer polyjacking for more damaged and delicate slabs.
Repairing a concrete slab with mudjacking will last between five and 10 years on average. However, the number also depends on the cause of the issue in the first place. If the concrete slab is damaged because of drainage issues, it's important to fix the root cause of the problem to keep the structure from sinking further over time.