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Facility Maintenance Decisions

Planning Paints and Coatings Applications That Deliver Benefits

Effective paint selection and surface preparation can help managers and crews deliver applications that look good and last

By James Piper, P.E.   Paints & Coatings

OTHER PARTS OF THIS ARTICLEPt. 1: This PagePt. 2: Paints and Coatings Finishes Contribute to Performance, AppearancePt. 3: Surface Preparation Dictates Success of Paints and Coatings ApplicationsPt. 4: Paints and Coatings: Contractor Considerations
Painters with building exteriorEven the highest-quality paint will not perform well if the surface is not properly prepared before painting.Sto Corp.

Maintenance and engineering managers often take the process of specifying paints and coatings for granted. Too often, they pay more attention to the cost and the color of the paint than the appropriateness of the type of paint for a particular application in an institutional or commercial facility. The result often is poor performance, poor appearance and early failure.

Managers can avoid these issues by understanding their options when it comes to paints and coatings. One size does not fit all. Different applications have different requirements, and success requires matching the characteristics of the paint to the performance requirements of the application.

A number of specially formulated paints exist for special applications, the most commonly used general categories of paint are water-based latex and oil-based or solvent-based products. In latex paint, the majority of the liquid is water. In oil based paint, the liquid consists of a number of organic solvents. Each has its own performance characteristics that affect the way they perform in different applications.

Latex vs. oil-based paint

About 75 percent of the paints and coatings market is for latex paint. Part of its popularity is due to its easy cleanup with soap and water, fast drying time, and environmental restrictions on the use of some of the ingredients in oil-based paints, but latex paints also are widely accepted in the commercial and institutional marketplace due to their performance advantages.

Latex paint is easier to apply than oil-based paints due to oil paint’s consistency, which creates a heavier drag to the brush or roller. Workers can apply latex paints more smoothly and evenly and with less brush drag. They offer good adhesion to most surfaces, as well as better elasticity than oil-based paints.

In exterior applications, latex paints offer better color retention and chalk resistance than their oil-based counterparts. Latex paints do not get brittle with age, and they resist cracking better than oil-based paints. Their high binding properties provide good protection against blistering and peeling, and the addition of mildewcides limits the growth of mildew.

In interior applications, latex paints are relatively odor free while drying, and they do not have issues with the release of volatile organic compounds (VOC) common to oil-based paints. Again, the quick drying time of latex paints allows workers to apply a second coat in a few hours, as opposed to a few days with oil-based paints.

Latex paint is a proven choice for woodwork, drywall, masonry, galvanized metal, and aluminum, although workers should only apply latex paint specifically formulated for masonry surfaces to concrete, brick, and concrete blocks.

Latex paints are best applied with a roller or a synthetic bristle brush made from nylon and polyester. Natural brushes made from animal hair tend to clog with paint, producing an uneven finish.

In contrast to latex paints, cleanup of oil based paints requires solvents, such as turpentine and paint thinner. They produce a higher level of odors than latex paints and might require that areas of a facility be taken out of service while they dry. Drying times are typically 12-24 hours.

Oil-based paints do offer better adhesion to heavily chalked surfaces, and they are better at preventing existing stains from bleeding through the paint. They are more resistant to wear and tear, and for high-gloss finishes, they can produce a smoother finish with fewer brush marks than latex paints. But their hard finish is less flexible and can become brittle as it ages.

Oil-based paints perform particularly well on a building’s interior wood trim, including baseboards and windows. Baseboards typically need to endure a great many bumps and scrapes, something the hard finish of oil-based paint tend to withstand better. When applied to windows, oil-based paint limits the sticking of the sashes.

Oil-based paints are best applied with natural bristle brushes made from animal hair. These brushes tend to deliver the most consistent finishes.

For both latex and oil-based paints, managers need to focus on quality, not cost. A top-quality paint can perform well for up to 10 years, while an average-quality paint might last only three to four years. And since the major component of cost in a painting project is labor, skimping on the cost of paint actually increases the life-cycle cost of the painting project.

How can managers ensure they are getting a high-quality paint? In general, the higher the paint’s cost of the paint, the higher its quality. But do not rely on cost alone. Look at the paint’s percentage of solids, which remain on the surface after the paint cures. A higher percentage of solids means more paint on the surface.

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  posted on 1/15/2020   Article Use Policy

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