How to Repair Concrete

It is important that you know how to repair concrete because there are many places around the home that have concrete. Learning about the techniques used for patching holes in walks or driveways can improve the safety and beauty of a home.


1. Cracks in Sidewalks - The Safety Issue

Repairing concrete is not only for aesthetic reasons but for safety reasons as well. If there are cracks in sidewalks or driveways it can be unsafe for foot traffic and vehicle traffic. From repairing hairline cracks to patching up holes in concrete walks and driveways repairing concrete is an important job to know how to do. It also can save you a lot of money learning how to repair concrete, as you will not have to hire a professional every time there is an issue with the concrete around your home.

When concrete cracks appear in sidewalks, it is important that they are repaired quickly. The cracks are unsightly and take away from the overall look of the outside of the home, but the most important reason for repairing the concrete is for safety reasons. When there are cracks in a sidewalk, it is very easy to trip on them, especially for children. Many children play on the sidewalks and if there are cracks in it there is more of a chance that they can become injured. This is especially the case for children, as well as adults, that ride a bicycle or a skateboard over the sidewalk. Tires and wheels can get caught in the cracks and increase the chance of falling, which is very dangerous not only because of the fall but because the sidewalk is right next to the street. If an adult or child falls on the sidewalk there may be a chance they will also fall onto the street into oncoming traffic. Due to the latter fact, it is important to repair concrete on sidewalks as soon as you see cracks appear.

2. Cracks in Driveways - The Safety Issue

Much like cracks in sidewalks, it is also important, in terms of safety, to repair cracks in concrete driveways. Cracks in concrete driveways makes it more likely that people will trip and fall, especially children who are riding bicycles and skateboards. Larger cracks in a concrete driveway also make it more likely that a vehicle will have trouble.

From a bumpy ride to people inside the vehicle, because of the crack, to damage to the vehicles tires, it is important to fix concrete cracks in driveways as soon as they appear. If there are children living in the home, many times, they will play in the driveway and having cracks in them will only increase the chance of them becoming injured. To ensure the safety of the people in the house, as well as others around the home you should have a driveway that is free of cracks.

3. Repairing Concrete Cracks - Aesthetic Reasons

Just like cracks in anything else, a crack in a concrete driveway, walkway, or sidewalk does not look good. An unsightly crack in concrete around the home looks bad and makes the outside of the home look bad as well. What makes concrete cracks looks even worse is that many times with letting the crack stay unfixed grass and weeds can begin to grow out of the cracks, which look very bad. The concrete is supposed to be smooth and have a look of evenness to it. However, with cracks, weeds can begin to appear and they also make the driveway, walkway, or sidewalk look uneven, which takes away for the symmetry of the outside of the home.

Everyone has seen homes that have large concrete cracks around them and how bad it can look, as no matter how beautiful the home looks the outside of the home is the first thing that people will see. To keep the outside of your home looking great it is important that concrete cracks are repaired as soon as they appear. This is especially the case if you are looking to sell your home because the more cracks are present the more it will take away from the value of your home.

4. The Importance of Repairing Concrete Cracks as Soon as They Appear

It is very important that once concrete cracks appear that you repair them as soon as possible. Once cracks appear in anything they will get bigger. This is the case for anything that has a crack but even more so with cracks in concrete driveways, walkways, and sidewalks. The reason for this is there is more pressure put on the cracks with foot traffic and especially vehicle traffic. A crack in a driveway will become larger quickly because of all the weight of a vehicle continually passing over it making it bigger.

It is also more cost effective to repair concrete cracks as soon as they appear. The larger the crack the more difficult it will be to repair. If the crack becomes too big, you may even have to hire a professional to repair it. Larger cracks will require more work and more supplies, such as more concrete, so repairing the crack as soon as you see it will make it so the crack does not get bigger, which only leads to more headaches and more repairs. If you see a hairline crack, repair it ASAP so it does not become a bigger crack.

5. Preparation when Repairing Concrete

Just like with any other job preparation of repairing the concrete is the most important step. Make sure you have the right cement or pre-made adhesive for the job. You can use tools such as a metal trowel, a wood float, and a putty knife for applying the new cement adhesive. For cleaning and enlargement of the crack, you can use a chisel, hammer, rubber mallet, a wire brush, and a broom.

Make sure before you start to repair the cement on a sidewalk or driveway that you have either some plastic sheeting or a wooden board large enough to cover the repaired area. When the weather is hot and windy do not repair concrete cracks, as it can make the compound dry too quickly. Also, do not repair concrete if the weather is freezing as the patching will not take and it may freeze. The best time to repair cracks in concrete is when it is around 50-70 degrees and overcast.

6. How to Repair Hairline Concrete Cracks

It is not difficult to repair hairline concrete cracks, as you simply need to get a little bit of cement mixed to fill the crack. When you get the cement, only add enough water to it to make a thick paste. Along the hairline crack, moisten the area for a few hours before applying the grout, as this will keep it from drawing the water from the grout and not dry it out. The area of concrete where the hairline crack is should be moist but make sure there is no standing water in that area.

After letting it moisten for a few hours clean the area off and then apply the grout with either a putty knife or a trowel. Try to force the grout into the hairline crack, as much as you can, and then smooth it off making it level. Let the patched hairline crack to dry for a couple of hours and then cover it with either a plastic sheet or a wood board. You should try to keep the area covered for around 5 days. Every day take off the covering and sprinkle a little bit of water over the area. After about 5 days, the crack should be fully sealed.

7. How to Repair Cracks in Concrete Sidewalks

Sidewalk cracks must be made larger before they are repaired, as you can do this by using a chisel and a hammer. You need to make the crack larger at both the bottom and the top, as it will help the new concrete bond better with the old concrete. Make the undercut of the crack about 1", as the depth of the undercut will depend on the depth and size of the crack. Remove all the debris by using a wire brush.

If you use a concrete adhesive, the concrete will hold better, as you should brush the adhesive into the area you undercut and let it dry so it becomes tacky. If you do not use adhesive moisten the cracked area but make sure there is no standing water. You can use a concrete patch that is pre-mixed for smaller sidewalk cracks. If you use your own patch, use 1 part cement and 2½ parts fine sand. For larger cracks use 1 part cement, two parts of sand, and three parts of gravel. After applying the patch tamp it down tight in the area that is undercut. Make sure that all the areas of the crack are completely filled.

When the mixture starts setting, you can smooth it down with a metal trowel or a wooden float. For a smoother finish use a trowel but for a rough surface use the wood float. When you are done patching the crack let it dry for a couple of hours and then cover the area with a plastic sheet or wood board. Keep the patched area covered for around 5 days. Every day lift the covering and wet the patched area, as this will allow the concrete to cure.

8. How to Repair Cracks in Concrete Driveways

Repairing cracks in a concrete driveway is done much like repairing cracks in a sidewalk. However, the main difference is the crack must be repaired to withstand more pressure, as vehicles will be going over the repaired area. Because of this when you use a mix you should use a gravel mix instead of a sand mix. To make this mix use 1 part cement, 2 parts sand, and three parts gravel. Just like the sidewalk, you will need to clean the crack and then undercut it.

The more depth there is to the crack the stronger the area will be once repaired. After undercutting and cleaning, follow the same steps as repairing the crack in the sidewalk. Just like the sidewalks, you can level the patching using a metal trowel or a wood float. Cover the area that is patched with a plastic sheet or wood board and wet the area each day for 5 days. Make sure you do not drive your vehicle over the area that you patched for 5 days.

If the crack is a larger or deeper one you may want to wait a week to make sure the crack is fully repaired. By driving over the patched area too soon you will increase the chance of the crack reappearing because of the increased weight applied to the cracked area. There are also rubberized sealants, especially made for driveways, you can use but it will not actually repair the crack but simply fill it in with rubber.

9. How to Repair Cracks in Concrete Walls

To repair cracks in a concrete wall follow the same steps as repairing a crack in driveway and sidewalk. However, there are a few things that are different when repairing cracks in a concrete wall. After you clean the area of the crack, use a stiff wire brush to clean off the debris but make sure that you do not make smooth edges. Rough edges on the wall will allow the new concrete to bond better with the old concrete. Use the same adhesive that you would for a sidewalk but use a wire brush to apply it to the crack.

If the cracks in the wall are smaller, you can also use a ready-made concrete patch. Make sure you use enough pressure to completely fill the crack. To conceal the patch better on the wall try to match the original finish of the wall. To do this rough up the wall while you can still work on it, as you can use a float, broom, or other tool to get the rough finish you want. After cleaning the area, apply the adhesive using a trowel. Wet the area after applying the cracks in the same way as you would a driveway or sidewalk.
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