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If you have a sidewalk on your property, odds are you're going to have to repair it at some point. Concrete is a durable, versatile material, but there are many factors that can lead to a damaged sidewalk. Roots can crack pieces and push them out of alignment, cold temperatures and ice can lead to damage, and normal wear and tear can create dangerous situations or unsightly problems. We're going to go through some basic sidewalk repair and show you that with a little know-how and some standard tools, you can do it yourself and do it right.
Some concrete basics: concrete is a composite material made from a few different elements. It combines fine and coarse pieces held together by a liquid cement binder. This means that getting the right mix of water and concrete is key to the right strength and drying time. Check your package instructions, but generally you're looking to create a peanut butter consistency. Concrete works best between 50 and 80 degrees Fahrenheit. When there is no range, there are lots of different types of concrete that you can find at Lowe's, covering all kinds of applications: water resistant, fast set, high-strength, reinforced with fiberglass, and even countertop style. Make sure you choose the type that is recommended for your project.
There are two levels of sidewalk crack. The first is a hairline crack, like this. The second is a wider crack, like this one. For a hairline crack, remove any loose debris from the damaged area with a wire brush and broom. Then you can use a caulk gun loaded with a masonry crack filler to fill the crack, or you can use a vinyl concrete patching agent and a putty knife to fill it in.
For a wider crack, you will need to use a small sledgehammer and a chisel. You want to make the bottom of the crack wider than the top, which sounds tricky, but it just means angling the chisel like so. This will help lock the patch in place and keep it from moving. Clean the debris with a wire brush and broom in the area, and then fill the crack with a vinyl patching mix and a trowel.
Now, we've all seen concrete like this before, with crumbling edges and missing corners, but don't worry, we can fix that too. I will say, if it's more than just a broken edge or a missing corner, you may have to replace the whole section. But if it's a localized problem, you can fix it. First, clean out all the debris with a wire brush and a broom, and chisel out until you have strong concrete on all sides. If this piece will see a lot of traffic or weight, like a concrete step, then you'll want to drill out a hole with a masonry bit first. Take a piece of steel dowel, like this, called a rebar rod or rebar, coated with a latex bonding product, and insert it into the hole halfway. Apply the same bonding product to the broken edges of the sidewalk, making sure to get into all of the crevices. Mix up your concrete patch with water and add some of the bonding product to the mix. Read the manufacturer's instructions for specific amounts. Use your scrap wood to create a form for the concrete to shape to. Put your mixture into the form with a trowel, tamp it down, and smooth out the top. You can use a broom to lightly score the top for a texture. Leave those boards in place for a week until it dries, and then you'll be good to go.
When a piece of your sidewalk is too damaged to use, it can be best to just rip it out and start over. First, you will need to remove the existing sidewalk piece. Once the piece is gone, clear any rocks or debris from under the spot where you will put the new slab. Dig around the edges to create a perimeter. Then it's time to build a form. You want the top edge of the form to be even with the existing sidewalk so it all sits flush. Use stakes or scrap wood to hold your form in place, and place the stakes regularly to avoid the form from bowing outward. Make sure the stakes sit below the top edge of the form, or else cut them flush. Spray the inside of the form with oil for a clean release. Put a couple of inches of sand in the form, then mix your concrete and pour it into place, making sure to get into all the corners. For an easy way to find out how much concrete you'll need, check out Lowe's concrete pad calculator at Lowe's.com.
Then comes the screed. Screeding is when you use a longboard to flatten the concrete. Move it slowly from one end to the other with a short sawing motion, and add concrete to any low spots as you go. Then lightly smooth the surface, but be careful not to dig the float corner in, or you will have to rescreed. Let the concrete dry for 30 minutes, then use a broom to create a non-slip texture. Lightly place some plastic on top and let it dry for several days. Remove the plastic and let it dry for a couple more days, and then you can remove the forms and replace the dirt around the edges.
We've covered everything from tiny cracks to replacing whole sections. While some of it can be time-consuming, you can do it yourself, and you can do it right with Lowe's. Good luck.