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Can You Slabjack Concrete That Has Been Mudjacked in the Past?

cracked walkway

If you’re researching this question, you are probably already familiar with concrete leveling or concrete lifting methods.  If you’re not, or if you’d like a quick refresher on the topic, let me recommend this article that explains how concrete lifting works.  We explain the process of concrete lifting (and leveling) and include a side-by-side comparison of the two most common methods: mudjacking and slabjacking.

Acculevel has been repairing foundations since our beginning in 1996.  When Andy Beery first started the company, mudjacking was the only reliable concrete leveling method available.  Like most industries, new techniques or repair methods are developed.  After extensive testing and research, Acculevel decided to invest in this more efficient process that uses polyurethane foam as lifting material.  Since 2015, we’ve had consistent and remarkable results with this faster and cleaner method we refer to as slabjacking. 

In this FAQ blog, we’re going to discuss a question we’ve been asked by a number of homeowners.  If your concrete slab* was mudjacked with lackluster results, can Acculevel slabjack this same section with greater success?

*Slabjacking can be used on a number of concrete surfaces or structures around your property: patios, driveways, fireplaces, walkways, porches, garages…


Mudjacking Can Inhibit Slabjacking

We can slabjack a concrete section that has previously been mudjacked.  However, it may not be as successful as you’d like.  The mudjacking process creates some less-than-ideal conditions for a second lifting attempt.

The Weight Has Increased

Mudjacking doesn’t use wet dirt as its fill type, of course.  The “mud” is an industry term for a type of slurry; usually it’s a mix of concrete, sand, limestone, and water.  It’s essentially a diluted  version of concrete- kind of like an industrial grout.  

Essentially, the “mud” slurry is not a lightweight material and it has formed a new layer below your existing slab.  It may or may not be attached to the slab itself, depending on how much material has been put into place.  But either way, the resulting consequence is the same: slabjacking has to be inserted below both the slab and the mudjacking layers. 

To slabjack, we will have to drill through both the original slab AND the additional concrete “mud” to reach unaffected soil.  Depending on the age and condition of these elements, we could be trying to lift two heavy and thick concrete segments, not just one.  Additionally, we will have to drill a new series of injection holes through the concrete; we cannot re-open and inject through the holes created during the mudjacking process.  However, the drill size needed for slabjacking is ⅜” so it is significantly smaller than mudjacking drill of 1-2”. 


Decay Can Be an Issue

If the mudjacking was done more than a year or two ago, It’s already beginning to crumble at the bottom and edges. This is because it’s just a thinner version of concrete; it’s susceptible to the same wear and tear as your original slab.  

Slabjacking is environmentally friendly and is safe for use in residential areas, but it is not a weak process.  It starts as a liquid that seeps into any and every possible crevice, fills it, foams up, then moves on to the next open space it finds.  

The polyurethane fill exerts significant force when it foams up.  One of the possible side effects of this process is it might accelerate the breakdown of the “mud.”  When that happens, the mudjacking layer is flattened or crushed, absorbing the impact of the foam.  This inhibits the lift that we are trying to reach and reduces the efficiency of slabjacking.   


Do You Have a Concrete Slab You’d Like Evaluated? 

If you have a slab that has been mudjacked before, or you’re interested in having repairs made to a concrete structure on your property, find an experienced and reputable concrete contractor.  We strongly recommend that you check the Better Business Bureau before you make any decisions; the BBB will help you determine if the contractor is accredited and insured.  

Please take advantage of our free checklist of questions you should ask a contractor, to ensure they are the right company for you. 

If you live in our service area, please contact Acculevel for a free estimate.  One of our experienced project managers will evaluate your foundation condition and recommend the best course of action for you, to keep your home strong and healthy for years to come.

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