REPAIRING CONCRETE AND STUCCO
FOR SMALL CRACKS IN STUCCO OR CONCRETE
These can be patched with concrete patch. This comes in tubes that are used in a caulking gun. Larger cracks can be filled with concrete patch that comes in a container that looks like a big round Elmer's Glue bottle. You cut the end off of the pointed cap. You apply the fill through that hole by squeezing the container. Clean the crack out as well as you can with a small screwdriver or something similar. Clean out the dust & debris, and apply the concrete patch by caulking gun or squeezing the patch into the crack from the container.
FOR CRACKS THAT ARE LARGER
Patching cement is needed here. You can use a regular sand and cement mix, or buy something easy to use like Redi Lok. That company distributes gallon containers of cement, or for wetter applications, hydraulic cement. I use hydraulic cement for outside applications where the concrete is exposed to rain and dampness. These can be bought at your home supply store.
To get the best cement bond, use a chisel to chip out and widen the crack to at least a half inch wide. Undercut the crack so that it's wider on the inside than it is at the surface. This dovetail type undercut will help the cement bond and not fall out.
A stiff brush will clean out dirt, dust, and other debris. If you mix the cement, empty some on a piece of plywood and mix it up according to the bag's directions. If you use a canned mix like Redi Lok, just follow the directions on the can and dip the cement out of the can. The mix you use should be stiff enough to hold its shape when applied, but not too dry so it crumbles when you spread it.
Wet the crack with water before applying cement. Trowel the patching cement on to the crack. It needs to be packed in firmly. Feather the edges of the patch with the trowel, or with a wet cloth, being careful not to make streaks or grooves in the patch. It starts to somewhat stiffen.
Smooth of any excess after it starts to set a bit. To get maximum strength from the repair, keep it somewhat damp for about 24 hours by occasionally spraying it with a fine water mist.