How To Stucco
Learn how to stucco! A stucco finish on the outside of a home adds charm and beauty to the structure by blending in with the landscape around it.
In some areas of the southwest, homes covered in stucco abound. This cement based siding provides great insulation during the arid, hot summers and windy, freezing winters. A stucco finish on the outside of a home adds charm and beauty to the structure by blending in with the landscape around it. Stucco is popular for these reasons but even more so because of the ease of making repairs.
Stucco comes in a premixed, dry form that with the simple addition of water becomes a medium with which to work. It can also be made by combining one part portland cement, three parts building sand and enough water to form a putty like mixture. It is necessary to apply stucco over masonry or concrete, although in some cases it is applied to a wire lath on a wooden frame.
If you are making repairs to an existing stucco wall you can purchase the dry mix in 90 pound bags from a lumberyard or home center. Be sure to check the color of the stucco you are repairing to insure that you get the necessary pigment coat for your stucco as well. When you have your stucco mix at home you will need to pour part of the dry mix into a large metal bucket or wheelbarrow. The tools you will need to do this project, including the wheelbarrow, can be rented from a local tool rental store. Add water to your stucco mix and stir with a hoe or shovel. For smaller amounts a good sturdy stick can be used to stir the mixture. You will need to continue adding water to the mixture and stirring until it is the consistency of putty. Be sure you never start a repair job with stucco when a freeze is threatening.
For smaller cracks you will need a stiff putty knife to cut open the crack all the way back to the sound stucco. Using a cold chisel and a hammer, undercut the crack so that it is wider inside than it is on the surface. Rake away any loose materials inside and around the area of the crack. Then wet the crack using a sponge and clear water. Use your putty knife to fill in the crack, packing the stucco tightly as you go. When you notice that the crack extends to the base materials, be sure to overfill it slightly. Allow the stucco to dry for approximately 15 minutes and then work it into the crack with your putty knife. Remove any excess stucco from the outside of the wall and moist cure the patch with a fine spray from a garden hose. This should be done once in the morning and again at night for a period of three days.
Larger cracks or breaks will take a bit more work to repair. Be sure when working with large cracks or breaks that you have enough dry mix on hand to complete the job before you start. In this case you will need to scrape away the damaged stucco down to the base material. If the surface is masonry or concrete you will need to wear goggles and wire brush the entire surface. Cut slightly into the mortar joints with a cold chisel and hammer and then clip off and replace any damaged lath. Thoroughly douse the entire area with water and, using a rectangular trowel, scrape the stucco from a hawk onto the wall in a 1\2 inch thick layer. This coat of stucco is better known as the scratch coat. Next, press the stucco through the lath to embed it. You will omit this coat of stucco if your base is made of masonry or concrete. Once this coat of stucco is firm but not set, score it with a scratcher made of nails driven through a board. Scratchers made just for this purpose can also be purchased at your local hardware store.
You will need to allow the scratch coat of stucco to dry for five to six hours. Then dampen it again. If your base was concrete or masonry you will do this just before you apply the second 3\8 inch thick layer of stucco. You should then rub this coat with a wood float which can be rented at you local tool rental store. All the entire wall to moist cure for 48 hours and then for at least 5 days prior to applying the final 1\8 inch to 1\4 inch thick coat. If needed you can then add the pigment while mixing this final coat of stucco. Use a trowel to apply the final coat and then texture the patch with a stiff brush, trowel or wood float. Be sure you are following the existing design in the stucco so the patch will match. Allow the finish coat to dry for 24 hours and then moist cure it for another 24 hours.
When you are starting from scratch with a stucco wall you will need a larger quantity of materials. If your wall requires one to three cubic yards of stucco you might want to rent a portable mixer. Be careful when doing this that you do not exceed the capacity of the mixer. Each batch of stucco should be mixed at just over half the total volume of the mixer. Unlike concrete you will also have to be careful with the consistency. While concrete is an medium that is poured, stucco has to have a putty like consistency to be properly applied. It is best to begin at the top of a wall when you apply stucco and work toward the base. Because of its consistency, stucco tends to dry out quickly so it will be necessary to fill in small areas and then move to the next. Be sure you take time to insure that all of the base is well covered before moving to another area. The drying time on full walls are the same as when filling in cracks or holes.