Most interior primers are designed for very specific applications. Often, they serve a practical purpose by warding off potential problems that might arise due to the nature of the surface being painted, or the environment in the room. Other times, they serve an aesthetic purpose; namely, enhancing the appearance of an interior paint job. And they always enhance the adhesion of the top coat of paint to the surface below. So, it is wise to use primers to achieve the best interior painting results.
Many interior primers come in both latex and oil based formulations, so you often have a choice of products to use. Keep in mind, however, that latex products are much lower in odor, which is a significant advantage on indoor projects.
Here are some of the most common types of interior primers and the situations in which you should use them:
These interior primers protect the new coat of paint against “bleed through” of staining matter like dirt, grease, rust, smoke residue and waterborne material by sealing off the stain-producing agents.
While they are called primers, these coatings actually serve as sealers over drywall and joint compound to give the top coat of paint a uniform appearance. Despite the name, you can generally use them on new plaster as well… but first, check the directions on the label.
Vapor Barrier Primers
These primers are useful in bathrooms, kitchens, laundries and other damp rooms, where they help minimize the passage of moisture out through the walls. By doing so, they reduce the chance that exterior paint will fail, or that wall insulation will become saturated and lose its effectiveness. They also help maintain a comfortable level of indoor humidity during colder months.
Latex Enamel Undercoaters
Using these primers under semigloss or gloss paint helps ensure that the top coat of paint will form its maximum gloss and have a uniform look. For best appearance, you should lightly sand the primer to remove brush marks and/or any fibers that may come from the surface being coated.
These specialty primers are designed for use on very slick or glossy surfaces such as glass, tile, Formica®, or vinyl-coated paneling (but not countertops). Their purpose is to help form a secure primer-top coat paint system.
The core content for Painting Tips is provided by the courtesy of Dow Chemical as found on CaliforniaPaints.com.