The Right Way to Repair Water-Damaged Concrete Slabs
Learn how to handle water-damaged concrete floors and how the professionals carry out repairs.
- Water damage can quickly ruin a concrete floor
- Some damage is easy to repair by grinding and coating the floor
- Other situations will require more intensive repairs
Remember that big, intimidating biker who sat behind you during the IMAX showing of Titanic, then you turned around at the end to see him weeping into his engine rag? That’s concrete. It’s rock solid and tough, but it also has a vulnerable side.
One of concrete’s biggest menaces is moisture. Water can harm concrete over time in ways that don’t just make it look bad but also create health hazards and accidents waiting to happen. Discover how property owners and professionals can ensure concrete slabs stay as safe and attractive as possible.
How water worms its way into concrete
Spilled drinks. Cleaning products. Utility overflows. People dragging wet shoes all over it or leaving the slabs exposed to the elements. Concrete surfaces often must tolerate a lot of liquid, and every little drop brings them closer to deterioration.
Concrete, contrary to widespread belief, is porous and absorbs moisture. This can harmlessly evaporate given enough time, but environmental conditions don’t always allow it. If you see any of the following signs on your concrete slabs, it means repairs are necessary:
Dark spots or isolated areas of faded color could mean moisture damage is already underway. If the discoloration is dark green or black, you may have mold in your slabs that can harm your health. White spots may mean a buildup of salt called efflorescence. This can come from water vapor or alkali in the concrete being pulled to the surface by water.
These are either caused by existing water damage or are an invitation for moisture to move in. Don’t make the mistake of dismissing small cracks! Even the slightest surface opening is a perfect entry point for spills, droplets, and even vapor to start quickly weakening slabs.
- Paint peeling
Common in commercial concrete slabs, peeling paint is caused by laminated flooring being weakened by water, resulting in loss of paint adhesion. Efflorescence may be to blame. You may also see bubbling paint or vinyl, which is a sure sign of water issues.
Spalling? Appalling. Spalling is pitted or flaking concrete that looks terrible. It’s common in colder climates and poor blending practices. It is caused by the expansion of trapped, pore-clogging water. Pitting involves small holes that create Swiss cheese-like slabs highly vulnerable to moisture entry.
You’ll be doing your concrete floor a solid when you let professionals assess and repair any signs of damage. Here’s what you can expect when they get there.
How the experts tackle water-damaged concrete
Professionals do four things before selecting a repair method:
- Consult with the customer about their goals
- Assess the surface
- Decide on the best repair method
- Test on a small part of the floor
Your contractor may use shot blasting. This is a fast and effective way to get rid of water-damaged paint or other surface issues by, well, blasting it with metal beads to pulverize the top layer. This process has its pros and cons.
The good: It’s a chemical-free process with easy clean-up and can add texture for slip resistance.
The bad: It gets tricky around the edges, so a less-experienced team may do a shoddy job.
Sometimes the answer to water damage is more water. Repair teams may hydroblast damaged slabs which, like shot blasting, strips away any compromised coatings so new ones can be applied.
Diamond drills and concrete mills
Grinding away the offending layer with diamond-coated pads (who said concrete wasn’t glamorous?) is another way to remove damaged surfaces. This process can also leave slabs looking polished to perfection if they’re ground long enough.
One drawback is that this can take a while, depending on the degree of damage and the desired effect. The longer the job takes, the greater the wear and tear on the contractor’s tools and the higher the expense.
Milling is another possibility. This process uses diamond-tipped blades on a rotating drum to remove upper layer stains and issues, preparing concrete for coating or other work. Sometimes repairs must be even more extensive. This is generally when the problem has gone deeper and has become a potential structural risk, which may require involvement from experts in other structural fields.
What happens after surface repair?
Your contractor will then suggest multiple ways to recoat concrete slabs. This could mean applying a resinous coating or multiple layers of moisture-resistant polyurea concrete floor paint – a highly durable and flexible elastomer that’s also heat and chemical resistant. Polyurea is often combined with an epoxy basecoat and primer for superior protection.
Sealed concrete is the solution for some slabs. Polishing is perfect for others. We’ve previously covered the difference between them. Briefly:
- Polished concrete flattens, densifies, and seals concrete. It’s cost-effective, durable, and may need only quick sweeping to maintain. It’s not great for kitchens, bathrooms, or anywhere acids are used.
- Sealed concrete fills any concrete gaps by creating a film over the floor’s entire surface. It’s tougher against stains than polished concrete, and the right sealer can stop moisture from getting to your floor. It’s high-gloss, low-cost, and installed quickly while minimizing damage from the freeze-thaw cycle (which causes concrete to expand and contract). Cons are higher susceptibility to damage in high-traffic areas and less water resistance.
“Why would I want the one with less water resistance?” We hear you. But sometimes, it’s not what a customer wants but what their specific structural situation dictates. Contact the concrete professionals to ensure you’re making the right decision.
We’re your solution to water-damaged concrete slabs
We can find you an experienced team to repair anything from cracked concrete to more serious issues. Even if we can’t do it ourselves, we can help you create a plan to get it done. Give damaged concrete slabs the care they need today, and you’ll be spending less on maintenance tomorrow. Visit our contact page to ask any concrete-related questions or discuss your project needs!