Is Your Concrete Driveway or Sidewalk in Need of Repair?
With the economy being in the shape it’s in, more and more people are holding on to the homes they have rather than upgrading, resizing, etc. This trend has natural consequences, such as the need for people to do more repairs and routine maintenance on their existing homes as time passes.
As homes age, an increasing number of homeowners are noticing that concrete driveways, sidewalks and patios are showing signs that they’re in need of repair. The problem areas tend to range from small cracks or small areas of scaling to larger cracks, spalling, pop-outs, and break-offs. As with almost all problems, if addressed quickly, they can be remediated at lower cost than if such problems are allowed to continue to go unchecked. Problems areas in concrete that should be addressed immediately are large cracks, serious spalling, corners that are broken off, or areas that are heaving or sinking.
Naturally, concrete repairs can be very expensive, so I’ve found most people would prefer to do the work themselves, assumiung they have the knowledge to do so. Thus, here’s some tips on doing some of the more basic concrete repairs….they’re not difficult to do, and don’t require expensive tools.
Many homeowners have successfully made repairs to their driveways themselves, benefiting from significant cost savings. For those with driveways in need of repair and who have the skills and inclination to make their own repairs, here’s some basic information that should be of value. A Master’s Hands, LLC does not warrant the accuracy of this information, or accept any liability associated with the use of this information – it’s provided solely for our readers’ convenience. If in doubt, contact a professional concrete repair service.
Repairing Cracks in Concrete
There are a number of simple methods that can be used to repair cracks in concrete. The appropriate method to use depends on the severity of the crack, whether it’s located indoors our outdoors, and whether you plan to paint or stain the concrete afterward.
First, you should know that not all cracks in concrete need to be repaired. All concrete is guaranteed to crack sooner or later. That’s why contractors include grooves (called control or expansion joints) across the surface of concrete. Those joints are meant to intentionally weaken the concrete in those particular spots to give the concrete a natural “weak” spot in which to crack. When cracks occur along these joints, the cracks are much less noticeable. In most cases these cracks along expansion joints don’t become a problem as long as there is a proper sub-grade layer through which water can pass, such that water doesn’t remain standing in the cracks, where it can freeze and cause further cracking.
More often than not, repairs made to minor cracks can be more unsightly than the cracks themselves. Cracks 1/8-inch or less in width can usually be left alone without further damage occurring. This rule-of-thumb assumes you have a proper sub-grade, and also assumes the crack wasn’t caused by an entire section breaking off and separating completely from the rest of the surface (such as when a heavy weight is applied on a corner that breaks through). The most common cause of such “break-offs” is a heavy truck or other vehicle driving over the surface, close to the edge where underlying support is weaker. Thus, always be careful about having heavy vehicles drive on your concrete driveway. If they must do so, be sure to have them stay away from the edges of the surface.
If a small untreated crack grows larger, or you see the concrete chipping away along the crack, you should address it by having some repairs done. However, repairing concrete cracks won’t always solve the problem if the concrete isn’t structurally sound – such as when the cracking is being caused by movement in the earth below…such as in areas troubled by expansive soil (e.g. bentonite, etc).
If a crack has quickly opened more than ¼-inch in width, or there is vertical displacement (one side of the crack is higher than the other), you should consult a contractor for structural problems and solutions.
Methods for Repairing Simple Concrete Cracks:
For small cracks, use a wire brush to remove any loose debris and rinse thoroughly with water. Allow the crack to dry completely. Use concrete / mortar repair or epoxy crack filler (in a caulking tube, with caulk gun) to fill the crack. Force the material down inside the crack with a thin object such as a putty knife. Then smooth out the surface with a trowel, or with your finger.
For larger cracks, clean, rinse and let it dry. Then chisel out the crack to create a backward-angled cut, using a cold chisel and a hammer (see figure). This shape, along with the bonding adhesive, helps keep the repair material from loosening or popping out of the crack. Mix a batch of concrete patching material according to the supplied instructions. Fill the crack with the patching material, making sure it is forced well down into the concrete, filling the entire crack if possible. Then smooth out the surface with a trowel.
For even larger cracks follow the cleaning directions above, then pour sand into the crack below the top surface. Prepare sand-mix concrete, adding a concrete fortifier, then trowel the mixture into the crack, feathering until even with the surrounding surface.
When the patching begins to harden, scrape off excess down the sides of the crack and smooth out the repair with a soft, wet brush. An old paintbrush should work well.
Repair concrete cracks when the temperature is above 50 degrees (F) and overnight temperatures are not expected to drop below freezing the next few nights.
If you plan to acid stain your concrete, be sure the caulk or patching used for any repairs contains cement or cementitious material. If not, the acid won’t react properly with the patches will be left uncolored by the stain.
Don’t do repairs when it’s too hot or too windy. If you do so, the material will dry out too fast, resulting in a weak repair. If repairs in such conditions are unavoidable, then secure a plastic sheet covering over it, and/or take steps to shield it from the sun.
After your repairs are fully cured, if they appear significantly darker in color than the surrounding concrete, try rubbing the patched area with a flat stone. This will turn the repaired areas of concrete white, making it less noticeable.
After you repair cracks in concrete, it’s always a good idea to put a coat of concrete sealer over the area to help prevent water seepage. This will help your repair last longer.
Spalling / Scaling
Concrete spalling and scaling are common occurrences, especially on exterior surfaces that are exposed to many freeze and thaw cycles. The difference between the two situations is that spalling involves bigger chunks breaking loose. There are many causes of spalling, including improper finishing methods and curing methods. Scaling on a properly finished and cured surface is most often caused by the use of salt or other de-icing chemicals on the surface, especially in the first year or two after the concrete has been poured, or later on when the surface has not been recently re-sealed.
Popouts are a fairly common occurrence on exterior concrete surfaces. They are small, conical pieces that break away from the surface, leaving a shallow divot. This happens when aggregates near the surface split or expand, creating pressure and causing pieces of concrete to pop out of the surface. Fortunately, with spalling, scaling or popouts, simple repairs can be performed to fill the voids, which will help prevent further deterioration, as well as improving the look of your concrete walk or driveway.
How to Repair
- Chip out the edges of spalled/scaled or popout areas, and use a hose to clean out the area. Brush away all loose debris and concrete chips. You may wish to use a pressure washer, if available. Clean the area thoroughly with water and use cleaners to get rid of oil and grease or anything that might inhibit bonding of the repair. Then let it dry fully.
- Mix up a batch of concrete repair mortar. If the damaged area is deeper than an inch, add some small gravel to the mix, such as pea gravel. Make sure the repair mortar contains a bonding agent, or add some liquid bonding agent to the mix. Anything that says acrylic, vinyl, or latex on the label should contain a bonding agent.
- Place the mortar in the hole and smooth with a trowel. Don’t overwork it.
- When the patch begins to harden, brush it lightly with a damp brush for a better appearance.
- For curing, brush some clear sealer over the surface before it gets too hard and begins turning white. If you don’t have any sealer, keep it covered with a damp towel or other covering for a few days.
Tips on Maintenance Following Your Repairs:
- No foot traffic on the surface for at least 36 hours, and no vehicle traffic for at least a week.
- Apply concrete sealer after resurfacing has hardened, and once a year in the fall if you live in a harsh climate.
- Use de-icers that DO NOT contain any calcium or sodium chloride.