Priming Walls: Myths and Reality—is it Necessary to Prime Before Filling

Explore common myths and realities about priming walls, and learn when it is truly necessary to prime before filling for smooth, lasting paint results.

A lot of DIYers pick up primer before they have done any patching, under the mistaken impression that it’s a necessity. In reality, not every wall needs it, and forgoing the process can save time and money. Primer works well on bare drywall and on highly absorbent surfaces such as new masonry or walls with stains, though using too much won’t add strength. In other cases, primer can weaken the bond, or it becomes an adhesion problem if your application is too fresh.

LBC Capital research shows that homeowners who skip unnecessary priming save both time and materials without affecting long-term results. This article busts myths and explains when a primer can really help you and how to fill and finish walls like a pro. By the time you’re done, you’ll know what sticks and what doesn't—and how to skip unnecessary steps.

When Priming Helps

It really does make a difference on new drywall or plaster. Naked surfaces absorb filler unevenly, showing patches when they receive a sanding and paint. For example, a 12×12 ft (3.66 m) section of new drywall requires 0.5 gallons (1.89 l) of joint compound without primer but only 0.3 gallons (1.14 l) with primer. That’s a 40% material saving.

Primer seals and protects the surface, making it more uniform for easier painting. Without it, patch jobs will be patched themselves, and paint can settle differently throughout the wall. On extremely absorptive walls, skimping on primer can mean extra sanding and even a second coat of paint, at $25-$40 in materials.

The walls, with their water stains or smoke and crayon marks, bleed through fillers and paint. Stain-blocking primer seals in the discoloration. Without it, you could end up painting twice if using light colors. In real life, putting on some primer is easily a savings of $20-30 (and repeat) per wall in filler and paint. The nuance is timing: apply the primer only after the wall has dried all the way, or any trapped moisture may spoil adhesion.

High-Traffic Areas

Primer is a good product for high-traffic rooms such as kitchens, hallways, or children’s rooms. The Ible look-alike in the can is wonderful; it penetrates the filler or whatever and makes a layer between the filler/paint, which will make it last a long time. Walls that are primed before spackling can save 30–40% in touch-ups over the course of 10 years, which means everyone saves time and money. If you pass on primer here, that means more repairs and less even wear.

Filling Without Primer

Hairline cracks, nail holes, and small dents are unlikely to require primer. Spackling can be applied directly to the painted surface. A 2022 U.S. DIY survey revealed that 68% of minor repairs avoided primer and had no visible issues a year later. Priming small spots is a waste of time for the most part.

Priming gives you more dry time—typically 1-2 additional hours per coat. On a clean, previously painted wall, you can double your painting time by skipping the primer. For anyone looking to knock out three rooms over a weekend, that’s 2–3 hours of time saved, and for those wanting to work faster without sacrificing the job.

Common Priming Myths

There are many who feel that primer makes the just-working joint compound stronger. It doesn’t. Drying time determines compound strength. A typical drywall patch is fully cured in 24 hours with or without primer. Adding primer won’t stop cracks that develop when the wall moves or settles.

Cracking occurs due to changes in the framing, temperature, or subsidence. Primer can’t prevent walls from flexing. Excessive priming can also capture moisture under the filler, exaggerating cracks. A cracked wall does not a primer problem make—it's structural.

Not all surfaces need primer. Don't expect round-the-clock cries of the sky is falling, but glossy paints, latex finishes, or sealed walls tend to adhere easily. Using primer here is redundant. In simpler terms, using it when you don’t need to will waste your time and $15-$25 per gallon, will not improve your results.

Primer doesn’t hide sloppy patching. If you have uneven sanding or excessive filler, it will come through any amount of primer. The reason you can get away with not using primer on small repairs is because filler and paint can be smoothed between successive coats. When you misunderstand primes, it’s all for naught.

Costs and Savings

That comes out to an extra $15–$25 per gallon for primer. One coat is all you need to cover a 12×12 ft wall; however, applying more will only require spending more. Avoiding primer on minor repairs saves $5–$10 a wall and $20–$30 across three rooms.

Each of these walls adds 30–60 minutes for priming, plus drying. It would save you 3–4 hours on spots if you didn’t already have a primer in a three-room renovation. That time means labor saved if you hire help, or it allows DIYers to complete the job more quickly.

Priming is only worth it on bare, porous, or stained surfaces. Over a decade, properly primed walls require 30 to 40 percent fewer touch-ups. Misusing primer on itty-bitty jobs is just a waste of time, money, and energy.

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