HOW TO FILL IN CONCRETE CRACKS FOR THE DIYer

​Before beginning to repair cracks on your driveway or sidewalks you will need to completely clean the surface and get rid of any loose dirt or debris. Using a pressure washer is ideal but a garden hose
can also be used for smaller cracks. Begin by washing the entire concrete surface or if the cracks are limited to a small area, you can just get away with cleaning that one area. You will want to thoroughly clean out each crack, removing all built up dirt and debris. You will need to make sure nothing is left in the crack in order for the filler to properly bond and repair the crack. Once you have all of the debris blown out of the crack you may need to also use a screwdriver and hammer to chip out any additional loose material that doesn’t dislodge using the water. In addition to clearing out dirt and debris you will need to make sure that all vegetation is removed from the crack as well. Larger and more stubborn plants make need to be sprayed with roundup or burned with a propane torch.

Typically, concrete surfaces like driveways and sidewalks are about 4 inches deep however it is only
necessary to clean about ½ inch deep for the purposes of filling a crack. Many filler products will
advise the user to fill in cracks more than ¼ inch deep with sand. If you are filling in with sand before
the filler is applied you will want to make sure the sand is damp and tamped in as firmly as possible
with the goal of providing a firm foundation for the filler to rest on.

Once all of the debris and vegetation is cleared out of the cracks you will need to wash the surface
once more with a pressure washer or garden hose. Let the concrete sit and dry and then you are
ready to begin repair those cracks!

Filling and Repairing Concrete Cracks
Now that your concrete surface is cleaned and prepared it time to fill in those cracks and restore it to
its former glory. If you are using a cement caulk filler you can simply squeeze it into the crack slightly
higher than the surrounding concrete and then smoothed down with a trowel to make level with the
adjacent surface.

If you are using a cement based filler product you will need to first mix the material. Mix and use this
type of filler quickly as it will harden and dry very rapidly. Most manufactures of these products
recommend that you only mix enough for about 20-30 minutes of work in order to avoid wasting the filler. I recommend using a small pail to mix the filler in and then wash the pail and tools in between batches in order to prevent hard chunks of cement building up. The cement filler compound should be mixed a little thinner than cookie dough, not thin enough to pour but still thin enough to fit into smaller cracks that you may be filling. A rule of thumb is that if you can form a ball with the compound it is still too thick. Once you get the filler to the right consistency you can use a trowel corner or small kitchen spatula to force the filler into the cracks. You will want to make sure the filler actually gets down into the cracks and not simply cover the surface. Unless you have plans to resurface your driveway or sidewalk in the near future you will want to make sure you smooth out the filler overflows to create a level surface. Your newly repaired concrete surface will be ready for foot traffic in just a few hours, however vehicles will need to be kept off the repaired surfaces for about 3 days.