While it may be tempting to skip the primer when painting drywall, it's never a good idea.
by Bob Graham
thankless jobs that consumes time and money, yet remains invisible when the project is completed. So it’s easy to skip, especially if there’s a rush to finish a job.
But drywall primer is literally the glue that binds paint to the surface to which it’s being applied, and its properties cannot be faked by applying additional layers of a topcoat. Even though this important preparatory step doesn’t appear to make a difference immediately, its benefits become increasingly apparent over time, primer manufacturers suggest.
“Priming drywall is one of those things that good painters will do,” says Jeff Spillane, senior marketing manager for Benjamin Moore & Co., maker of a wide line of primer and paint products. “Preparation is 90 percent of proper painting, and priming is a big part of preparation.”
Benjamin Moore’s research shows that large contractors are most likely to prime before painting, while residential contractors, identified as those generating less than $1 million in annual revenues, are much more likely to skip priming.
That simple decision can be costly. “Two coats of cheap flatwall paint cost more than tinting one coat of primer if you are trying to get out of a house,” says Tim O’Reilly, primer categories manager for William Zinsser & Co, makers of Bulls Eye 1-2-3 primers.
“An improperly primed surface also can significantly affect sheen and other properties such as topcoat color, stain- or odor-blocking and even the quantity of topcoat that ends up being used for the job,” says Michael J. Walsh, vice president of marketing and new product development for the Masterchem division of Masco, which makes the KILZ brand of primers.
Not priming before painting can lead to a reduced pigment ratio, meaning in simple terms that the paint will lose some of its color, especially with darker hues. When darker colors are being painted, tinted primer is more effective than applying additional topcoats.
Unprimed painting degrades the performance characteristics of many paints. For instance, applying two coats of a premium product rather than one coat after priming will lessen the paint’s stain release and washing capabilities, Spillane says. The effects won’t be seen immediately, but long after the painting contractor has moved on, when the homeowner struggles to remove routine dirt and grime from the surface. In cases where light colors are used, say a cream or eggshell, the result is a marred painting surface that people often wrongly blame on the paint, not a lack of priming, experts say.
“We really recommend priming because it can eliminate potential problems, especially with sheens,” says Jonathan Knutson, Rodda Paint’s sales manager. Knutson says the company encourages “everyone from the architect to the customer” to use primers before painting.
To the uneducated eye, primed and unprimed walls, once topcoats are applied, appear similar. Primer makers admit that contractors can sometimes get away with using two topcoats, especially when lighter colors are being applied. But what these contractors might gain in speed, they will lose in the wallet when forced to pay for additional topcoats. A tinted primer is cheaper and more effective, especially for darker hues.
Priming is “unrewarding” for contractors so they avoid it to save money and time, says O’Reilly. Contractors seeking to cut costs should try another approach. “If you want to cut anything, cut out the cheap flatwall,” O’Reilly says.
A good primer coat assures good sheen, helps with the removal of paint or wallpaper, and lessens the chances of damage to the wall surface when future work is undertaken, says Bob Maversen, chemist and technical director for Scotch Paint, a Gardena, Calif.-based maker of the Draw-Tite brand of primers.
“The binder or resin content in paint can be absorbed into the drywall or spackle randomly, which will leave an uneven surface with visual variances, especially with contractor-grade wall paints, since they are typically low in binder content,” Walsh explains.
Paint and primers have different characteristics, so primers cannot be paint and paint cannot be a primer.
Dick Hardy, president of the primer manufacturer XIM Products Inc. of West Lake, Ohio, says priming a surface offers two key benefits. Primers provide a seal, effectively blocking out the penetration of paint into the drywall. Additionally, the application of primer creates a uniform surface.
Gray board, green board or waterproof drywall, and drywall mud or spackle each has a different composition. The key difference is the water content. The variance in water within each affects its porosity. Primers are chemically engineered to equalize these differences, thus giving a consistent surface on which to apply paint or wallpaper. A uniform surface is essential to avoiding bubbling and poor adhesion of wallpapers.
“Primers are formulated to provide a good base,” says Hardy, whose company provides a variety of primers for specific situations.
That consistency of a good base enables the paint to do its job evenly and effectively. Without proper drywall priming, the paint is more likely to peel off, the durability of the paint is lessened, and more of the pigment in the paint is lost to bleed-through, thus lessening the coloring ability of the paint, Spillane says. Semi-gloss and low-gloss paints absolutely require priming.
“Putting on a good coat of primer allows paint to really be paint, not primer,” Hardy says. “Then, paint can do what it’s supposed to do — create a consistent color on a surface.”
Experts suggest that primer always should be applied before texturing, and in an ideal world, after texturing, too, to provide a consistent surface porosity. “Doing both would be wonderful,” says Rodda’s Knutson, adding that priming before texturing is imperative.
Some primer experts suggest that the application of primer also assists with insulating. Several companies have advertised their primers as providing insulating qualities.
Spillane, whose company’s products do not advertise insulating qualities, can explain the logic, but isn’t sure if there is science behind it. Primers, especially alkaloid-based versions, provide a barrier, thus cutting the air vapor and moisture that can penetrate the substrate. A sealed substrate might help prevent cold air in the winter or hot air in the summer from penetrating an exterior wall. But the amount of air it keeps in or out is probably minimal, Spillane says.
So even though it is an invisible act, choosing to prime a surface before painting pays off in the long run. And most importantly, the experts agree, a properly primed surface shows off in the appearance of the final topcoat, which is the ultimate indication of whether a painter did his job well and whether he might earn additional business from the job.