Concrete Slab Repair: Common Issues & How to Fix Them
May 21, 2020
Concrete is a pretty tough material, but it ages just like everything else — and aging can cause some serious issues. Many common problems can be solved with DIY concrete slab repair solutions, but certain issues will require professional assessment for the best (and safest) results. Learn more about the issues you may already be experiencing in your home and the concrete slab repair methods that can fix them.
Common Concrete Slab Issues
Concrete slabs serve many purposes on residential properties: they're used for house foundations, driveways, outdoor patios and indoor porches, to name a few. When they're installed and cured properly, you don't have to think about them much outside of general maintenance to keep them looking good (if they're visible). However, if something went awry when they were laid, or other aspects of the build site were not accounted for, then you may begin to see some of these problems as time goes by.
Scaling
Scaling is one of the more minor concrete slab issues. It describes the degradation of the slab's surface, which can look like pits or "scales," to a depth of 1.5mm - 5mm in the first year after placement and hardening. It's a problem that can be caused by improper concrete curing, but also from prolonged exposure to de-icing salts — it is often hard to tell whether the installer or the homeowner is to blame.
No matter whose "fault" the scaling is, it can be indicative of concrete with poor strength. To repair concrete slabs with scaling, you'll need to rough up the surface of the slab, cover it with resurfacing concrete and apply a waterproof finish after it cures to protect it from moisture, de-icing salt and other destructive forces.
Cracking
Cracks are some of the most common and problematic signs of aging in concrete. In many cases, they begin on the slab's surface and get deeper over time — they can even split the slab if left unaddressed.
Cracks can be caused by several different factors, like drying shrinkage, subgrade settlement or supporting a load beyond what it was designed for. Shrinkage cracks are generally a minor flaw, while bigger settlement cracks suggest that the build site wasn't adequately prepared before the concrete was poured. Either way, cracked concrete can let in moisture that will freeze and thaw over time, worsening the problem. At their worst, foundational cracks will even begin to degrade the rest of your home's structure. When you notice a split in your driveway, foundation or other area of your home, you need to make concrete slab crack repair your top priority.
Buckling & Upheaval
Buckling is a problem that generally occurs with outdoor structures like driveways, basketball courts or patios. Common culprits of this issue are large trees with roots growing underneath the structural slab, as well as intense freeze-thaw cycles. It may start small, but as buckling progresses, the only way to repair it is to completely remove the problem area and replace it.
Upheaval is a similar issue that occurs with foundation slabs. It can be caused by tree roots, excessive moisture in the soil it was built on or an overall poor foundation design. Severe cases of upheaval can cause your doors to stick, walls to crack and counters to become unlevel. Like buckling, the best concrete slab repair methods will involve replacing and sealing problem areas.
Settling
Settling is the opposite of buckling — it's caused by the foundation of a structure sinking into the ground over time. It's a natural process, to an extent, but if cracks begin to form in your home's foundation, basement or walls due to an uneven concrete slab, it has progressed too far. One of the best ways to repair concrete slabs in this instance is to install helical piers or other reinforcements to slow down the process until other measures can be taken.
DIY Concrete Slab Repair
Certain kinds of slab concrete repair can be done by anyone with the right materials. For example, small cracks of about 1/16 inch can be remedied with concrete caulk, just like using spackling paste for nail holes in a wall. If you have cracks in your driveway, basement or foundation that are less than 1/4 inch wide, you should be able to repair them in a few simple steps:
- Using a hammer and chisel, open up the base of the crack into a V shape. This will help you dislodge any loose material that would get in the way of your concrete patching compound.
- If the materials in the crack are dry, use a wire brush or broom to remove all of the debris. If there is moisture inside, or if you used a hose or pressure washer to clean out the crack, wait until excess moisture has dried.
- Mix up your concrete patching compound (like a concrete slab crack repair epoxy or grout) and fill the crack. A trowel will work best for this process.
- Puncture the compound with the trowel to work out air pockets and ensure that the crack is totally filled.
- Once the compound is level with the surrounding concrete surface, smooth it out and allow it to cure.
Equipment Needed to Perform the Rice Test
While many parts of the theoretical maximum specific gravity of asphalt test can be performed manually, the equipment we're suggesting here mechanizes several steps to decrease margin of error and produce more efficient, accurate results.
Once the compound has cured, you can paint or seal it for extra protection and aesthetic appeal. Note that, if the cracks in your concrete are larger than 1/16 inch - 1/4 inch, you should contact a professional before attempting to repair the area yourself.
Professional Concrete Slab Repair Methods
Sometimes it's best to just call in the pros. A professional concrete installer and repairer will have a wider variety of tools to not only fix the problem, but also identify what caused it and offer advice on how to prevent it from happening again. For example, they can use concrete moisture meters for fixing moisture problems, concrete slab grabbers for elevated slabs that need extra support or even an AMS sub slab GVP installation kit to assess vapor intrusion in building foundations.
A concrete moisture tester is one of the most useful and informative tools a specialist can use to find problems in concrete. Many instances of damaged concrete happen because of excessive moisture intrusion in the slab. A moisture tester can indicate the existing degree of saturation and, in some cases, the rate of moisture emission through the slab. With this information, the specialist can predict how the excessive moisture might affect the slab and get to work repairing or replacing it before movement or deterioration can do anymore harm to your home foundation or other structures.
Get Your Concrete Slab Repair Supplies from Certified MTP
Certified Material Testing Products is proud to offer a wide, high-quality selection of concrete testing equipment to help concrete installers create a proper mix design so that repairs aren't needed for years after the slab is laid. View our full selection today to find everything you need to install and repair concrete slabs.
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