High Style and Performance in a Single Product. Tough and attractive, textured coatings were designed to be applied over concrete, cinder block and stucco surfaces.
by Ester Brody
, contractors, architects and specifiers have come to rely on the tough, yet attractive finishes provided by textured coatings. Originally developed for the Federal Government Specification TTC-555 B that contains section 3.3.3 (wind driven rain test), textured coatings were designed to be applied over concrete, cinder block and stucco surfaces. Government specifications called for coatings that created a protective layer on these substrates that would provide waterproofing and enough flexibility to bridge gaps and cracks. The texture of the coating also helped aesthetically by hiding surface imperfections.
Today's contractor now has many textured coating products to choose from, each with its own performance properties. Selecting the right coating for a particular project will ultimately depend on which performance characteristics are most important to the success of a job. For exterior applications, the most important characteristics are waterproofing, flexibility over a broad range of temperatures and resistance to fading and dirt pick-up. Coatings must also form a permeable surface so moisture does not become trapped between the substrate and the coating. A permeable surface is also critical for interior applications where the formation of mildew can cause considerable damage along with unsightly surface staining and unpleasant odor. Just like exterior applications, flexibility and dirt resistance are also vital performance capabilities.
How a product will perform depends in large measure to the type of polymer used as a binder and the formulation of the product. Many of the textured coatings on the market are classified as elastomeric. Elastomeric coatings with 100-percent acrylic binders provide excellent flexibility, waterproofing and resistance to dirt and fading. What makes these coatings so desirable is their ability to provide a high-build finish that is waterproof, yet permeable. When applied to the exterior of a building, the coating can expand and contract with the building movement. This capability provides a flexible layer that bridges cracks and gaps which occur on stucco, concrete and masonry surfaces. "These coatings are perfect for new and renovated buildings because they preserve the integrity of the substrate," says Ron Sibbrel, president of Life Paint in Santa Fe Springs, California. "Textured elastomeric systems that are made with 100-percent acrylic binders are a true solution to cracks and water damage that can occur when a building settles or is subjected to vibration or thermal expansion." Some of the other advantages offered by these types of coatings include resistance to dirt and moisture pick-up, fading and chalking.
Another category of acrylic textured coatings is solvent- or emulsion-based coatings that also have outstanding performance characteristics. The Vexcon Chemical Company in Philadelphia, Pennsylvania manufactures highly modified styrene acrylic polymers for solvent- and emulsion-based systems. These Vexcon systems provide a decorative film that covers surface blemishes and imperfections while offering excellent adhesion, weatherability and waterproofing. Ideally suited for application on masonry, block and stucco surfaces, these coatings are very resistant to UV light, molds and environmental chemicals. Unlike other textured coatings, these coatings can be applied above or below grade where they are subject to hydrostatic pressure. Another unique feature is that they can be applied on new or "green" concrete or alkaline surfaces without the aid of primers. "The polymers we use are specially designed to be alkali resistant," says Darryl Manuel, president of Vexcon Chemicals. "With our product, there is no need to wait for the concrete to cure before coating can be applied."
As with any coating systems, achieving the best outcome of a textured finish depends upon several factors. Selecting the right coating for the job is a critical step. Most textured coatings are made specifically for application on masonry, stucco and cinder block and concrete. Some can also be applied to properly prepared wood, and metal. In addition, textured coatings are also made for a variety of commercial (high rises, museums, hotels, tunnels, for example) and residential locations, and in rehab and new construction. "These coatings are extremely versatile," says Sibbrel. "Textured coatings offer application and performance advantages in interior and exterior locations, and in all types of weather."
Once the right kind of textured coating has been selected, surface preparation is the next key step in achieving excellent product performance. In general, any surface that will be coated with a textured finish must be free and clear of all loose paint, dirt, oils and mildew. In addition, efflorescence and chalk, which could affect product adhesion, should be cleaned away. Loose pieces of surface debris should also be removed. In most cases (except where noted by the manufacturer) new concrete should be allowed to age approximately 30 days before a coating is applied. To ensure a continuous coating application, all cracks, gaps and joints should be filled with a compatible compound recommended by the manufacturer. Applying an appropriate primer, if specified by the manufacturer, is the final step before the textured coating is applied.
How the coating will be applied is another consideration. Textured coatings come in a wide variety of profiles from smooth hi build systems to coatings that are filled with texturized material. As usual, always check with the manufacturer for application tips and recommendations. In most situations, textured coatings can be spray applied with specialized equipment designed to spray texture paints. However, textured coatings can be applied with a brush or roller in small areas. Special attachments to spray equipment may be necessary for some textured coatings, so be sure to carefully look over product literature for application recommendations. Some textured coatings can even be manipulated by hand with masonry or stucco tools after the coating has been sprayed on to the surface. "Many of the contractors we work with like to incorporate their own designs," says Sibbrel.
Finally, equipment clean up will be determined by the type of textured coating used: paint thinners are effective with solvent-based systems, and soap and water is suitable for water-based products.
Rob Rosson, product marketing manager at the Coronado Paint Company notes that textured coatings are gaining popularity over other products that have been used in the past. "In many installations like offices, hotels and hospitals, textured coatings have replaced vinyl wallcoverings because of their durability and resistance to mold and mildew." Vinyl wallcoverings create a vapor barrier that traps moisture. As a result, mold and mildew formation under these wallcoverings is not uncommon. However, textured coatings are made to "breathe" which allows moisture to escape. Another advantage offered by many textured coatings is their low odor and easy application. In most cases, applying these coatings is no different than other architectural finishes. Textured coatings are extremely durable and scrubbable, which make these coatings an excellent choice for high traffic areas like auditoriums, lobbies, and school buildings. "With all the advantages of textured coatings, we find that once a contractor uses it, they're really happy with the results," says Rosson.
In addition to the many interesting patterns and designs that can be created with textured coatings, a wide range of color choices is also possible. Sherwin-Williams for example, offers their textured coatings in hundreds of colors. Blending in with the design scheme and decorating materials used on a project is not a cause for concern. It is important for painters, owners, architects and specifiers to realize that these texture paints are high performance coatings that far exceed the functions of typical masonry paints. They will provide many years of waterproofing, extended service life and decorative treatment.