We hope you will find the following information helpful as you finalize your painting plans. The quality of a painting application is affected by many factors, the most obvious one being the quality of the paint. All paints have 3 components: the binder, the pigment and the liquid. The binder has the greatest influence on durability. Type and amount of binder affects everything from stain resistance and gloss to adhesion and crack resistance. Quality latex paints with 100 percent acrylic binders are especially durable. They tend to adhere well to a variety of surfaces, which affords them greater resistance to paint failure.
Oil-based and latex paints differ in their long-term durability. Most oil-based paints use mineral spirits as their main liquid component, while water is the carrier in latex paint. There can be some adverse consequences with oil-based paint. After several years, oxidation (the mineral spirits evaporate and leave a hard, tough film) renders the film not only hard but extremely brittle as well. As a result, when the surface expands and contracts, the paint film will stay rigid and may crack and flake. Latex-based coatings form their film in a much different manner. As the water evaporates, the latex binder fuses into a continuous, flexible film. Also, binders in quality latex paint tend not to be broken down by sunlight as quickly as the binders in oil-based paint.
Pigment is the second component or ingredient that helps determine the quality of the paint. “Prime” pigments provide color and opacity (visual obliteration of the surface being painted). Titanium dioxide, which is white, is the most common. “Extender” pigments provide bulk to the paint at low cost and contribute relatively little to color and hiding, compared to prime pigments. Higher-quality paints typically contain higher levels of premium pigment than do lower-quality paints. Better quality paints also have less extender pigment relative to binder level and are more chalk resistant, therefore providing better color retention and durability.
Top-quality paints typically contain a higher volume of solid material (binder and pigment) than do ordinary paints. In the case of top-quality latex paints, that means more solids and less water and explains why top quality paints perform so much better. Top-quality latex paints contain anywhere from 35 to 45 percent of solids by volume, while ordinary paints typically contain somewhere between 25 and 30 percent. A top-quality paint with 40 percent volume solids will dry to a film one-third thicker than a paint with 30 percent volume solids. A thicker dry paint film provides better hiding and better durability.
The preparation of the surfaces and method of application are also major factors in the appearance and life expectancy of the paint job. It is safest to choose a contractor who can supply references, and the homeowner should carefully check the references. Ask the contractor to prepare a “tech data” sheet. Information should include what surface preparation is to be done (scraping, caulking, power washing, etc), quality of paint to be used, number of coats, and method of application (brush, roller or spray). Brushing and rolling will work the paint into the surface. The most common application is spraying the paint onto the surface and then back rolling for penetration.
Professional painters will tell you that it is very important to maintain the siding of your house by repainting as soon as the need becomes apparent. If painting is not done in a timely manner, the siding can become damaged and will not accept the paint properly. If the siding deteriorates badly enough it will need to be replaced. The life of the paint can also be affected by the color. In general, lighter colors are more resistant to sun decay. On a hot sunny day in Colorado there can be as much as 25 degrees difference between a light and dark-colored surface.