The best primers are recommended to fix common painting challenges. Problems include stains on walls, moisture damage, old painted surfaces, odors, color changes, and new exterior wood.

What goes underneath the paint - primer - is one of the most powerful tools a professional painter can use. The primer is a fantastic problem-solver, resembling glue more than paint. As you prepare any surface for painting, it sticks to it and creates a smooth, uniform surface that's ready for painting.

However, if you've ever walked down a primer aisle at a home center, you know that there are tons of choices. Taking the clutter out of the equation, we compiled six of the most worrying surface issues house owners and managers are concerned about.

Stains and odors in the interior are a problem

Even after application of several coats of primer and paint, some stains will bleed through. Smoke from fires and cigarettes are other examples of severe odors. Several kinds of stain-blocking primer are available, including oil-based and water-based versions.

Despite giving off an unpleasant smell and requiring paint thinner for cleanup, oil-based paints are more reliable for preventing water-based stains and odors like rust, nicotine and smoke.

A water-based stain-blocking primer has the advantage of being easy to clean and posing no odor. Furthermore, it is available in low- and no-VOC (volatile organic compounds) formulations. Stains such as crayon, grease, ink and scuff marks that are absorbed by solvent-based fabric cleaners are best blocked. The two versions are both white, so if they will be covered with dark-color stain block paint, it makes sense to tint them gray or to make them similar to your topcoat color.

The New Drywall Problem

A different type of mud is used on drywall seams and the rest of the drywall absorbs paint differently. Several factors contribute to the appearance of blotchy, dull areas under the paint. This is also known as flashing, and it causes an inconsistent sheen. A drywall primer-sealer can help prevent this problem.

You can use drywall primer-sealer if your walls are perfectly smooth and you are an expert drywall finisher. As a result, your drywall probably has some small pockmarks, fine ridges and uneven paper scuffing from sanding. A high-build drywall primer-sealer provides the solution to those minor imperfections. Although it is more expensive than standard primer-sealer, this heavier-bodied product performs better as a leveling and filling medium for rough or uneven drywall surfaces.

You can also skip the primer altogether, especially if your drywall is relatively smooth and the finish is going to be a flat paint. Use two coats of high-quality, self-priming water-based flat paint instead. In self-priming paints, heavy-bodied paint resins seal the surface and fill in imperfections which are less obvious in flat paint anyway.

Areas prone to moisture are problem

Bathrooms, laundry rooms, closets, and kitchens have high levels of moisture that can cause paint to flake, crack, or peel. Peeling, bubbling, and blistering are common on exterior walls caused by moisture moving through the wall from the interior.

To minimize moisture passing through the walls to the outside, seal the surface with a vapor barrier primer. You can prevent mildew and peeling on interior walls by using a stain-blocking primer, or you can prevent blistering on exterior walls by using a stain-blocking primer. Prior to priming, make sure mildew has been killed with a one-part bleach and three-parts water mixture. Afterward, apply a topcoat designed to resist mildew.

Walls that have been repaired

In contrast to the rest of the wall, wall patches absorb paint differently than the rest of the wall. Using a primer-sealer on drywall prevents paint from soaking into the porous surface and becoming dull or blotchy. Cover all surfaces with a good-quality primer-sealer to prevent flashing, whether it's dabs of spackle or large patches of joint compound. You'll need a coat of oil-based stain-blocking primer if you're making repairs to plaster rather than drywall. It will lead to lime stains forming around the repairs and bleeding through the topcoat. Whether it's tiny touch-ups of caulking and spackling or major repairs of joint compound, it's important to be accurate.

Bare wood interior for new construction

To make the surface uniform and seal the thirsty surface, prime bare wood with a wood primer that hides imperfections and binds the wood fibers. An enamel undercoat primer, which dries slower than a water-based primer, provides superior adhesion and is easier to sand than water-based primers. When you apply a water-based primer, the wood grain is likely to be raised, and you'll need to sand it more before it can be painted.

Woodwork that has been previously painted

There's no need to prime an old coat of paint if it's in good shape. Using an oil-based enamel primer after cleaning and properly preparing the surface will prevent chalking and chipping of the paint. It is important to apply an undercoat primer to previously painted surfaces to ensure proper adhesion of the topcoat, as it creates a smooth, uniform foundation without laps or brush marks. Primers that dry fast, such as shellac and many water-based products, are brittle and scratch easily. There are chances of lap marks forming, which makes it hard to get a smooth topcoat base. Unlike oil-based primers, oil-based primers dry slowly; some take 48 hours to dry completely.

For a water-based product, you'll need a high-build acrylic-latex enamel undercoat that is specifically designed to be sanded. The door should be primed with a roller, while interior trim, such as casings, base, and door jambs, should be primed with the 2-inch brush. After the primer has dried, sand lightly to obtain a smooth paint job.

Final Thoughts

There are too many surface and paint defects that are quite tricky to address. Some require the expertise of seasoned painters, while some can be corrected through DIY hacks. If you are unsure of the most appropriate solution to your surface problems, we  our experts have decades of experience in applying the right primer to anything. Schedule a 20-minute consultation to find out more.