How to Choose and Use Primer

Solve common paint coverage problems with these expert tips for choosing and using primer

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Introduction

Painting pros recommend the best primers to solve common painting problems, including stains on walls, moisture damage, old painted surfaces, odors, color changes and new exterior wood.

One of the most powerful tools in any pro painter’s arsenal is what goes underneath the paint — primer. Primer is an excellent problem-solver that’s less like paint and more like glue. It sticks to whatever you’re preparing to paint and turns it into a smooth, uniform surface that’s ready for paint.

But if you’ve ever walked down the primer aisle at a home center, you know the primer choices are mind-boggling. To cut through the clutter, we asked three professional painters, each with 20-plus years of experience, to give us their recommendations for the best primers to use for common painting challenges. Their experience will help you choose the best primer for the job, so your paint will look better and last longer.

Project step-by-step (11)

Step 1

Problem 1: Interior stains and odors

Some stains will bleed right through most primers and paints no matter how many coats you apply. The same goes for severe odors like smoke from fires and cigarettes. The solution is stain-blocking primer, which is available in oil-based (alkyd) and water-based (acrylic-latex) versions.

  • Oil-based versions give off a nasty smell and require paint thinner for cleanup, but they’re more reliable for blocking water-based odors and stains like rust, nicotine, smoke, wood tannins and, of course, water (see “Shellac: The Original Primer,” below, for dealing with severe stains and odors).
  • Water-based stain-blocking primers offer easy cleanup and less odor and come in low- and no-VOC (volatile organic compounds) formulations. These work best to block solvent-based stains like crayon, grease, ink and scuff marks.
  • Both versions are white, so it’s a good idea to tint them gray or close to your topcoat color if they’ll be covered by dark-colored stain block paint.

Kilz and Benjamin Moore paint cansFamily Handyman

Do I Always Need to Prime Before Painting?

You don’t have to prime previously painted surfaces if the paint is in good shape—no chipping or peeling. Interior walls usually don’t need priming except in the case of stains, repairs or a paint color that’s drastically different. Interior painted woodwork usually needs spot priming with wood primer at a minimum. Exterior paint takes such a beating that it almost always needs priming with an exterior paint primer.

Step 2

Problem 2: New Drywall

The mud used on the seams of drywall absorbs paint differently than the rest of the drywall. This difference in porosity can cause blotchy, dull areas under the paint (a problem called “flashing”) and an inconsistent sheen. Prevent this problem by using a drywall primer-sealer.

  • If you’re an ace drywall finisher and your walls are perfectly smooth, you can use a standard drywall primer-sealer. But if you’re like most of us, your finished drywall probably has some tiny pockmarks, fine ridges and scuffed paper from sanding. The solution to those minor imperfections is a “high-build” drywall primer-sealer. This heavier-bodied primer-sealer is a little more expensive than standard primer-sealer, but it does a better job of leveling and filling in rough or uneven drywall construction. (Sorry to say that not even a high-build drywall primer can hide a terrible tape job.)
  • Alternatively, if your drywall is relatively smooth and the topcoat is going to be a flat paint, you can skip the primer and use two coats of high-quality self-priming water-based flat paint (see “Self-Priming Paints,” below). The heavy-bodied paint resins in self-priming paints seal the surface and fill imperfections (which are less visible in flat paint anyway).
    • Pro tip: Paint within 48 hours of priming. Many primers are formulated to physically and chemically bond with the paint applied over them. Once you’ve primed, you should paint over it within a couple of days or it will lose its effectiveness and you’ll need to prime again.