Things You'll Need
Epoxy fill kit
Paintbrush or sponge brush
Repairing cracks or chips in a horizontal concrete surface can be quite simple. Gravity allows the concrete to stay in place as it cures, ensuring that there is no shifting or other marring of the surface. Vertical concrete, however, such as columns, can be trickier. You cannot simply fill damage with new concrete, as it will slide down or fall away. The best way to make strong vertical concrete repairs is with an epoxy fill kit, available at most hardware and home improvement stores.
Rub over the damaged area with a soft but stiff-bristled cleaning brush, to release any loose particles. Rout the surface of the damaged area with a small router to make it as level as possible. Use the router to widen the damaged area a bit to hold the epoxy injection ports, if necessary.
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Clean the area to be mended so that all of the debris from routing is removed. Remove the injection ports from the kit. Separate the injection caps from the injection ports.
Insert one injection port at either end of the damage. Push the ports in as far as possible. Place the remaining ports evenly along the damage about every half inch.
Use a small paintbrush or sponge brush to apply a thin coat of epoxy adhesive to the surface of the damage. Apply adhesive all around the edges of the damage, as well. Work the adhesive close to each of the injection ports, but do not paint over them.
Allow the adhesive to set up so that it is sticky. Begin filling the injection ports with adhesive. Fill the lowest ports first and work toward the highest one.
Squeeze epoxy into the port until you can see the epoxy move into the channel of the port above it. Place a cap over the opening of each port once it is full. Let the epoxy dry two days once all of the ports are filled and covered.
Pry loose each of the injection ports. Remove the injection ports and dispose of them. Use a small putty knife to scrape away any dried epoxy that is where it shouldn't be.