How to Patch Exterior Stucco Cracks in a Soffit

Remove debris and loose bits from the crack with a dry, stiff cleaning brush or a toothbrush. Don't enlarge or further damage the crack with anything too big or hard. Brush the dust away from the crack with a clean cloth or an old paintbrush.

Insert the caulk tube into the caulk gun and slide the gun's rod forward until its end just touches the bottom of the tube. Cut off the tip of the applicator so it extrudes a bead of caulk about as wide as the crack. Follow the slanted guidelines on the plastic tip. If you're not sure, start at 1/8 inch and enlarge it later if needed. Use a utility knife or the built-in cutter that is part of many caulk guns.

Set the tip at one end of the crack and squeeze the gun's trigger to extrude and push a bead of caulk into the crack. Move the tip along the crack while squeezing the trigger. When the trigger hits a stop, let it go and squeeze again. Fill 2 or 3 feet of the crack.

Dip a finger in water, then use it to push the caulk into the crack and smooth it out. If you did a good job and applied just enough caulk, you won't have a lot of excess caulk left on the surface of the stucco. Carefully wipe away excess caulk with your finger or a dampened cloth.

Move to the next section until the entire crack is filled. Let the caulk cure for 24 hours before painting. If your caulk bead is 3/16 inch or greater, let it cure for at least 48 hours.