Why Use Stucco For My Home?
Stucco has been used in architectural structures since the Greek and Roman era and during the Renaissance. It spread throughout Europe and gradually became popular in America. Stucco is a finishing plaster composed of sand, lime, water and other ingredients. It is a strong, attractive and damage resistant covering for walls and ceilings. It is an excellent building material for hot areas as it helps to regulate the temperature. It is non-combustible and its surface burning properties include no flame spread and no smoke development.
Currently, there are two distinct types of Stuccoes –
Traditional/Hard Coat Stucco – This is basically cement mixed Stucco. The traditional stucco is durable and able to withstand harsh environments. It is porous and can breathe, so, dries quickly and resists water damage.
Conventionally, lime was used with sand and water. As lime is slightly soluble, the mixture has a self-healing tendency. At present, stuccoes are usually made up of Portland Cement, sand and water resulting in a hard and brittle variety.
To install hard coat stucco, first the substrate is installed followed by a metal lath and then a coat of stucco is applied with a trowel. It is allowed to set and then another coating is applied. Normally, the process involves a scratch coat, a brown coat and a finish coat (may be colored).
Stucco can also be applied on a paper and wire. The coats should be thicker. The first coat (scratch coat) covers the wire. It needs to be scratched as soon as it sets. The second coat (brown coat) gets bonded to this coat and as usual the finish coat is the outermost layer.
Synthetic Stucco – Since 1950s, a number of houses were built using a variety of synthetic materials resembling stucco. Fibers and synthetic acrylics were added to the cement stucco mixture to add strength and flexibility. In general though, the synthetic stuccoes are less heavy and hence, more susceptible to a hard blow. They are a one-coat stucco system unlike the three-coat traditional ones.
The most common one is EIFS or Exterior Insulation & Finish Systems. They are glued or mechanically attached to the substrate and usually composed of three layers. The innermost layer, mostly made up of polystyrene like material, is a foam insulation board. The second layer is a base coating attached to a fiberglass mesh and the final layer is a finish colored coat. It became popular because of its easy installation, low cost and better insulation properties. The only disadvantage is moisture absorption which causes water damage to the building.
A variety of stucco colors/paints are available. Colorants are inorganic pigments which can adapt with the high pH value of cement. They can be either natural like, Ochers and natural earths or artificial, such as man made Iron Oxides. Natural colorants remain unaffected to UV rays and are more pleasant to our eyes. But, the range of shades and the tinting strength is less when compared to manufactured colors. Man made colors, on the other hand, offer a wider range of shades such as dark blues and greens as well as various earthy tones like, yellow, brown and reds. They also possess excellent UV stability due to the presence of inorganic pigments.
The Next Generation of EIFS
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 cannot 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 sprayer 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 sufficiently because stucco is so porous. It may also require a second coat to cover small cracks and your repairs.