Should you always prime before painting? If so, how many coats of primer do you actually need? These questions will yield totally different answers depending on who you ask. This isn’t because no one knows the answer, but simply because the number of coats of primer differs from project to project.
Even still, the type of paint being used will determine how many coats of primer are necessary. Keep reading to learn when and when not to use primer, as well as how many coats of primer are necessary before painting.
What Is Primer?
Primer is a coat that comes before the final paint. Primer preps the surface to improve the paint’s adhesion and coverage.
Do You Really Need Primer?
Yes, you almost always need to prime before painting. The only time you can potentially skip primer is when you buy paints with primers built in. However, these self-priming paints are really only effective for painting over walls that already have paint on them.
Primer is beneficial for covering old paint and prepping it so the new paint adheres more effectively since it’ll aid in transitioning between paint colors. However, there are many other situations in which primer is absolutely necessary, such as:
- Painting unfinished wood: Bare wood does not accept paint as well as it accepts wood-specific products like stains and sealants. To help the paint stick, always prime unfinished wood before painting. For knotty wood, look for a primer that’s formulated to seal knots.
- Applying latex-based paint over oil-based paint: These days, most people are opting to use latex-based paint. However, there’s a good chance your existing walls are painted with oil-based paint, especially in older homes. To help the latex paint stick to the oil paint, you must use a bonding primer.
- Painting over plaster and joint compound: Walls that have been repaired or skim-coated with plaster and joint compound will look very uneven unless primed prior to painting. These repaired surfaces are filled with small imperfections and pores that will soak up the paint differently than the surrounding surfaces.
- Painting over new drywall: New drywall must be primed with PVA primer prior to painting. These special primers are extremely cheap, which is ideal for new drywall, as it soaks up a lot of paint.
- Painting over stains or mold: Stains from water, mold, and other substances can be very hard to cover, requiring many coats of paint. In the instance of mold, you run the risk of the mold still growing. Use stain-covering primers to cover ordinary stains, and opt for mold-killing primers before painting over moldy surfaces.
- Using lower-quality paints: Not everyone has the budget for high-quality paints touting excellent coverage. You can often get away with lower-quality paints by using a decent primer beforehand, which will save you money overall. Keep in mind, inexpensive paints may not last as long as high-quality paints, so saving a little money on the front end isn’t always worth it in the long run.
How Many Coats of Primer to Use
We’ve established that you shouldn’t skip primer, but how many coats of primer should you apply before painting? The number depends on the details of your project and the type of paint you’re using.
When to Use One Coat of Primer
Use one coat of primer when subtly changing paint colors or when going from a light paint color to a dark paint color. The primer will help cover the existing paint, allowing you to use fewer coats of your final paint, which is much more expensive than a primer.
When to Use Two Coats of Primer
Use two coats of primer for priming unfinished surfaces like wood, when drastically changing paint colors on painted walls, or when going from a dark paint color to a light paint color. It’s almost always difficult to hide the existing paint when drastically changing paint colors, but it’s significantly harder to hide dark colors under light colors.
To aid in coverage when drastically changing paint colors, ask to have your primer tinted to around 50% of your final paint color.
A minimum of two coats of PVA primer is necessary when painting new drywall in order to prevent the paint finish from looking splotchy and uneven after drying. New drywall is like a sponge, and it’s better to let it soak up inexpensive primer than expensive paint.
When to Use Three Coats of Primer
You may never need three coats of primer, but there are situations in which a third coat is necessary. If the second coat of primer hasn’t offered the coverage you’re after, go for a third coat before applying your final paint. This is more common when painting over abnormal surfaces like masonry, plaster, unfinished wood, and drywall joint compound, but may also be necessary to cover major stains, such as water damage on a ceiling.
What Type of Primer to Use
Consult the label on your primer for proper application. Different surfaces call for different types of primer and it’s important to use the right type. Read the label but, when in doubt, ask the associate at the store’s paint department for product recommendations.
When it comes time to apply your primer, pay close attention to the manufacturer’s instructions for application. These will specify how many coats of primer to use and any necessary steps to take between the coats, such as sanding.