Do i have to prime before painting

Applying a coat of primer before painting can seem like a waste of time to any DIYer in a hurry, especially since many paints come with primer formulated into them. However, in some situations, not taking the time to paint an entire surface with primer before a topcoat is applied can be a job killer.

Table of Contents Show

What Is Primer?
1. When Painting Brick and Masonry
2. When Painting New Drywall
3. When Painting Latex Paint Over Oil-Based Paint
4. When Painting Over Dark-Colored Paint
5. When Painting Wallpaper or Wood Paneling
When It's OK to Skip Primer
What happens if you don't prime before painting?
Is primer really necessary before painting?
Can I just paint over old paint?
Do you need to put primer on walls before painting?

“Think of primer as double-stick tape,” explained Joe Campbell, co-owner of Arizona Painting Company, the state’s largest painting contractor. “It helps the finish coat bond to the substrate you’re painting.”

Whether you’ve hired a contractor to do the work or are painting a surface yourself, pay attention to these situations where a separate primer coat is a must.

Scenario #1: Unpainted wood and drywall

Unpainted wood and drywall can pose huge adherence problems for coatings without primer. With fresh drywall, the substrate actually absorbs a coating really well, like a sponge. However, because it absorbs so well, without a primer coat, you’ll experience uneven coverage, especially along drywall seams. This means you’ll need to apply more paint to finally get an even coat. Even then, you may still find yourself repainting again sooner than later.

Unpainted wood is one of the most difficult surfaces to paint without primer. Unlike drywall, it is resistant to a coating. Without primer, applying even the highest quality coatings are an uphill battle that ends with shoddy results.

“Fascia boards are a common area where wood is exposed to the elements in Arizona,” Campbell added. “Even if the board needs some sanding and stripping prep to create a better surface for the paint, you still need that primer to get the coating to really stick well.”

Scenario #2: Dealing with paint peel

When paints fail, they start to flake and peel. The only way to repaint these areas of your home is to clean and sand away the failing paint. But with diligent prep work you’re actually working your way down to the bare surface. So, to repaint, primer is necessary.

“One of the most annoying tasks for a painter is to have to fix previously poor prep where someone didn’t remove the flaking and didn’t prime the surface. In time, that area of the job breaks down sooner than other areas that didn’t have flaking and peeling,” Campbell said.

Scenario #3: Unpainted stucco and concrete

Bare concrete surfaces and stucco (which is made with concrete) require primer before paint. Some concrete surfaces have a higher pH, which can create adhesion problems, Campbell explained. And other concrete surfaces may have efflorescence, a crystalline residue, on them. Both of these situations spell problems for a coating’s ability to adhere to the surface. There are great masonry primers that can overcome these situations, Campbell noted.

Scenario #4: Remedying chalky surfaces

When an exterior paint, like the ones applied to many of the Valley’s stucco homes, fails, you’ll often see a chalky residue on your hand if you wipe it across the surface. This happens as a result of all the binders and resins in the paint breaking down over time. The most thorough pressure washing job isn’t enough in these situations. A fresh primer coat is needed.

“If you clean the surface really well, you’re likely down to the bare substrate again, which will need primer,” Campbell said. “Even worse, if you don’t clean it well enough, the surface may have left over chalky residue and paint won’t adhere to that either.”

For these scenarios, Campbell also recommends a sealer for the paint as well.

Scenario #5: Painting over stains or glossy surfaces

Crayon marks, oil or other hard-to-clean stains need the help of primer to effectively trap and cover them while creating a clean slate that can allow a coating to adhere to the surface well.

“Other prep strategies like sanding or cleaning with degreaser will probably be needed, too, but just as is the case with chalky surfaces, cleaning isn’t enough. Primer is that final important prep step that will lead to a great final outcome,” Campbell said.

For other painting tips, visit the Arizona Painting Company blog; for a painting estimate, visit the Arizona Painting Company website or call (602) 648-3071 or (520) 284-1792.

Painting a wall is a big task in and of itself, so applying primer before painting can seem like an annoying extra step. It's almost always worth it to prime before painting interior walls because it helps the paint adhere to the wall, fills in cracks, and creates an even painting surface. But in some situations, you can skip it without risking ruining your paint job.

Video of the Day

What Is Primer?

Image Credit: Miljan Živković/iStock/GettyImages

See More Photos

Primer looks and spreads like paint, but it contains a higher concentration of solids as well as an adhesive binder. They can be oil-based, shellac-based, or latex-based. Because of the large amount of volatile organic compounds they release, the first two aren't suitable for interior use. Primers cover imperfections on your wall, hide stains, and prevent them from bleeding through the new paint, and create an even, blank canvas. There are five situations in which you should always apply primer before painting.

Tip

Most primers are white. If you're painting your walls a dark color, it pays to tint the primer, as it can make the difference between two and three topcoats. Ask the sales clerk to do this for you when you buy the primer.

1. When Painting Brick and Masonry

Image Credit: Siripak Pason/iStock/GettyImages

See More Photos

Brick and masonry are very porous materials. They'll readily soak up paint, which will leave you with splotchy, uneven paint. Applying primer beforehand will seal the masonry and provide a smoother painting surface so your paint job will look like it was done by a pro.

2. When Painting New Drywall

Image Credit: FotoDuets/iStock/GettyImages

See More Photos

Priming new drywall is always a good idea. Like brick and masonry, drywall paper and mud are porous materials. Primer seals the pores and evens out the surface. If you skip it, you won't be able to produce a uniform topcoat.

3. When Painting Latex Paint Over Oil-Based Paint

Image Credit: Paul Tamas / 500px/500px/GettyImages

See More Photos

Latex paint, which is water-based, doesn't adhere well to oil-based paint. If you're painting in an old house and you suspect the existing paint is oil-based, prime with a latex primer to ensure adhesion of the latex topcoat.

4. When Painting Over Dark-Colored Paint

Image Credit: Peter Schweitzer

See More Photos

Applying primer when painting over dark-colored paint is absolutely essential, especially if you're repainting it a lighter color. Otherwise, it could take several coats before you see a solid wash of color. Even then, the dark paint color could be tinting the lighter color, so you won't get the results you're seeking. Applying primer first fixes this problem.

5. When Painting Wallpaper or Wood Paneling

Image Credit: Stephen Paul for Hunker

See More Photos

If you're painting over wallpaper, whether vinyl or paper, apply a coat of primer first. Paper wallpaper absorbs paint and needs a primer to smooth things out and ensure an even topcoat. Vinyl wallpaper isn't porous, but it needs PVA or shellac-based primer to ensure paint adhesion.

The same is true for finished wood paneling. After de-glossing the paneling with a solution of trisodium phosphate and water, apply a coat of primer to prevent the topcoat from peeling or bubbling.

When It's OK to Skip Primer

Image Credit: eric1513/iStock/GettyImages

See More Photos

Primer isn't always necessary. Feel free to skip it if you're painting a wall that has been previously painted with flat (or matte) paint, especially if it is a light color.

Even if you do need primer, you don't always have to prime the entire wall before painting. If there is noticeable discoloration, you should spot prime with a stain-blocking latex primer to cover tannin stains or smoke damage. This is true for both previously painted drywall or wood-paneled walls.

What happens if you don't prime before painting?

If you skip priming, you risk peeling paint, especially in humid conditions. Moreover, the lack of adhesion could make cleaning more difficult months after the paint has dried. You may find the paint wearing off as you're trying to wipe off dirt or fingerprints.

Is primer really necessary before painting?

Priming is the foundation of a good painting job. Without primers, it is hard to achieve the perfect finishing. The primer provides a strong base so that the topcoat will bond to. The benefits of priming walls are many, including long-lasting, better protection, and stronger adhesion between painted walls.

Can I just paint over old paint?

If the current wall is smooth, clean and covered with the same type of paint (both are oil-based for example), you can head straight for the paint. You need to fill holes, spackle and sand*, maybe even cut a new piece of drywall in to the existing wall.

Do you need to put primer on walls before painting?

Apply primer before painting the walls. A primer is essential if you want to go from dark walls to light or white walls. Many brands offer paint and primer in one. First, use a paint brush to “cut in” 2- to 3-inch bands around the edges, corners and frames of a room.