Stucco is a cement-based siding product that is extremely popular around the country. Compared to other siding materials, it fairly easy to maintain and repair. This article discusses how to repair cracks and gouges, and painting stucco. Traditional stucco is a mixture of Portland cement, lime, sand, and water. It is usually about 3/4 inch thick, very porous, and holds on to paint very well. Color can also be mixed into the finishing coat of stucco, eliminating the need to paint.
Stucco is tough, but brittle and can sometimes crack as a house shifts or settles. Hairline cracks should not be repaired, so you do not have to try to repair every crack. If you can not get your fingernail into the crack, paint will usually fill it. For cracks up to 1/4 inch wide, you can repair them with a high-quality, exterior grade, acrylic latex caulk.
Clean loose debris out of the crack using a V-shaped object to get down in the crack. Then you can brush it, or use a vacuum cleaner. Caulk the crack with a paintable silicone caulk and smooth it out with your finger. Using your finger makes it easier to exactly match the existing texture. Use the 50-year kind of caulk for best results.
Wipe off excess caulking with a damp sponge in all directions to clean the rough texture. Here is a trick. Put some fine texturing sand in the palm of your hand and blow the sand to scatter it onto the wet caulk. This will roughen up the surface making it less noticeable.
Repairing wider cracks and gouges
For this job, you need to use a stucco patching compound. In order for the material to hold properly, exactly the right amount of water must be added. Follow the manufacturer's directions carefully. Thoroughly clean the crack or gouge as you did for small cracks. Use a putty knife or trowel to fill the area with a latex patching product. Thin the patch compound to the consistency of something like pancake batter. Dab a paintbrush into the wet material and holding one hand between the paintbrush and the wall, hit the brush handle against your hand splattering the material onto the repair area. This technique will match the texture of the surrounding stucco. You can smooth it out with a putty knife or trowel to the texture you want after the compound hardens a little bit.
For smaller jobs, use a roller. Use an airless spray for larger jobs. For best results, do not use a paintbrush for stucco other than to add texture. Spray the paint onto the surface and then use a 3/4 inch to 1 inch deep nap roller to work the paint into the surface for uniform texture. It usually requires two coats to cover stucco adequately because stucco is so porous. It may also require a second coat to cover small cracks and your repairs.