8 Times You Should Never Skip Paint Primer

How important is it to prime before you paint? In these cases, this step can make or break the outcome of your painting project.
A painter primes the wooden slats of a natural wood fence.
Photo: kelpfish via Depositphotos

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Is it really worth the effort and expense to prime before you paint? Absolutely. A primer preps the painting surface and seals any stains so that the paint adheres well, and you’ll get the smoothest, cleanest finish possible. In situations like these, however, neglecting primer can ruin the outcome of your project.

1. You’re painting latex-based paint over oil-based paint.

Person using paint roller
photo: iStock

You know the saying that oil and water don’t mix? Well, the adage holds true for paint. Latex paint, which is water-based, won’t adhere well to a wall that’s already been covered in oil-based paint, unless you prime first.

2. You’re painting brand new drywall.

Person standing on scaffold skimcoating drywall joints near ceiling.
Photo: iStock

Fresh drywall soaks up paint like a sponge, and the mudded joints take paint differently than the bare drywall between the joints. Translation: Without a coat of drywall primer, you’re looking at a splotchy paint job. Applying a primer prior to painting drywall will give your finished wall an even, clean look.

Zinsser Bulls Eye 123 Primer

ESSENTIAL GEAR

Zinsser’s Bulls Eye 1-2-3 primer will seal and prepare fresh drywall for paint, and can protect against mold and mildew. It covers stains, graffiti, wood tannins, and other discolorations and dries in just 35 minutes. It might be a bit thick for a paint sprayer, but since it’s water-based, thinning it out is easy enough to do.

Get the Zinsser Bulls Eye 1-2-3 Water-Based Primer/Sealer at The Home Depot for $29.98. 

3. You’re painting over unfinished wood.

Person rolls Zinsser primer onto pressure treated wood 2 x 4.
Photo: Tom Fenenga for Bob Vila

Bare wood is among the trickiest materials to paint. The natural fibers in the wood absorb a lot of paint, and variations in the wood grain can create an uneven finish. So, for the best results, always prime before you paint unfinished wood.

RELATED: Solved! How Long Does Primer Take to Dry?

4. You’re painting over a darker color.

Person using paint roller to paint a dark wall.
Photo: iStock

Dark interior paint colors are having a moment, but when the time comes that you’re ready to update your walls with a lighter hue, you’ll want to lay a coat of quality paint primer first. Painting a light color over a dark color typically requires multiple coats of paint to keep the old color from showing through the new shade. You can cut down on your work (and your costs) by priming the wall before you paint.

5. You’re painting over wallpaper.

Painting over wallpaper
photo: iStock Photo: istockphoto.com

Yes—in fact, you can paint over wallpaper. But you shouldn’t attempt it without priming first. On the other hand, if you’ve already removed the wallpaper, you need to prime the wall to correct any nicks or flaws sustained in the wallpaper removal process, in order to achieve the smoothest final finish possible.

6. You’re painting over a skim coat.

Man uses trowel to skim coat new drywall.
Photo: Lighthunter via Depositphotos

A skim coat is a thin layer of plaster or drywall compound that’s applied to smooth out the surface of a wall. This material is porous, which means it soaks up a lot of paint. To reduce the amount of paint required to cover the wall evenly, you should always prime a skim coated surface before applying color to the wall.

7. You’re painting masonry.

Primer being rolled over a  dark green wall.
Photo: iStock Photo: istockphoto.com

Masonry and brick are very porous surfaces and soak up lots of paint. On top of that, masonry surfaces have a high pH, which makes it difficult for paint to adhere. For this reason, before painting brick or masonry, it’s a good idea to prime it.

8. You’re painting a surface that’s stained.

Male hand uses paintbrush to apply primer to a mold-stained, dirty wall.
Photo: iStock Photo: istockphoto.com

If the wall you’re painting has had water damage or is stained in other ways, you need to prime before painting. You may even need to use a stain killer primer to ensure unsightly spots don’t bleed through your paint job.

 

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Jennifer Noonan

Contributing Writer

A confessed DIY junkie, Jennifer Noonan writes about home improvement, gardening, and all things do-it-yourself. The recipient of degrees in International Relations and Library & Information Science from Syracuse University, Noonan has worked in media and related fields for over 15 years, including her time at MTV Networks, where she served as Manager of Digital Programming at Nickelodeon. Today, Noonan lives in Delaware with her husband and daughters, where she is ardently teaching the next generation how to use power tools.


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