Tools and Materials
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What's Primer and Why Is Priming Important?
Primer is a base coat. It sets the stage for the main act — the paint — to shine. While there’s always the option to skip priming, you might not get the results you want. Here are several reasons why it’s a good idea to apply primer to walls before painting.
- It gives paint a better overall finish.
- It helps paint adhere better to a surface.
- You’re painting over a dark existing paint color with a lighter shade.
- Primer helps cover any stains on the walls.
- It lessens the number of paint coats needed.
- You're working with porous surfaces, like brand new drywall or bare wood.
- It prevents flashing, an unevenness in a paint’s sheen that can appear dull or shiny, caused by not properly preparing the surface before painting.
Primer is water-based or oil-based. Different types of primer are meant for different wall conditions and materials. Take note of what you're trying to cover and what you’ll be using primer on when selecting. Check out our Primer Buying Guide to make the best selection for your project.
If you’re not sure how much primer you need, our Paint Calculator can give you an estimate.
How to Use Paint Primer
First, you’ll need to prep the room you’re working in. Start by removing any furniture and other items. For things that can’t be removed, move them away from the walls toward the center of the room (if possible) and cover them with a drop cloth. Cover your floors with drop cloths, too.
If the walls are damaged, make sure they’re repaired before you prime. This could mean filling in any holes or cracks with putty and sanding rough patches. Vacuum and give your walls a scrub with soap and water to remove dirt and grime, which prevents the primer from adhering properly. Tape off the baseboards and ceilings with painter's tape.
Use our helpful guide on How to Prep for Paint for more in-depth tips and steps to get your walls ready for paint.
How to Prime Drywall
Step 1: Cut In and Spot Prime
To prime a wall, use a 2 to 3-inch paint brush to cut in the walls with the primer. This is simply outlining your walls with primer along the edges and in corners.
Next, focus on the areas of your walls that need extra attention, such as any stains or places where you’ve patched the drywall. Use your paint brush to apply primer to these specific spots.
Step 2: Apply the Primer
Stir the primer and pour it into a paint tray. Use a 9-inch roller to cover the larger areas of the wall. Make sure the entire roller is saturated with primer, then roll it over the ridged section of the paint tray to try to remove excess primer. Start by painting a vertical strip from the cut in corner, then continue applying the primer on the wall from top to bottom, working in sections. Be sure to overlap wet areas of primer.
If your project requires a second coat of primer, allow the first coat to dry according to the manufacturer’s instructions before applying the next coat.
Step 3: Sand the Primer
Once the primer has dried, use a fine-grit sandpaper to smooth out any roughness or bumps. This will help further prepare the wall to accept paint. Use a damp cloth or sponge to wipe away any leftover dust from sanding. Let the walls dry.
When the walls are dry, you can start painting.
How to Prime Wood Surfaces
Other surfaces benefit from applying primer as a base coat before applying the topcoat, like wood and metal. It's important to prep these surfaces so the paint will adhere correctly and give the surfaces a better finish. The primer you use should be formulated for these specific surfaces.
Step 1: Remove Old Paint
Remove old paint or paint that’s chipped or flaking by sanding or scraping it away. If you’re working with new wood, you can skip this step.
Step 2: Sand
Smooth the wood surface with sandpaper. For bare wood, use a fine-grit sandpaper. For previously painted wood, start with a medium grit to remove any remaining paint then switch to a fine grit to finish. Sanding gives the primer something to stick to so that it properly adheres to the surface. Wipe away any leftover dust.
Wear a dust mask or respirator and eye protection when sanding and follow the manufacturer's instructions for safe and proper use.
Step 3: Apply the Primer
Use a primer paint for wood surfaces. Stir the primer and pour it into a paint tray. Use a brush or roller to apply the primer. Refer to the manufacturer instructions for dry times.
Spray primer is also an option. It works well for projects like refinishing wood furniture.
Step 4: Sand the Primer
Once the primer is dry, use a fine-grit sandpaper to gently sand the primed surface. Wipe away any dust created by sanding. Your wood surface is now ready for paint.
How to Prime Metal Surfaces
It’s important to identify the type of metal you’re working on before choosing a primer. Metal falls into two categories, ferrous metal (steel, cast iron, wrought iron) and non-ferrous metal (aluminum, copper, stainless steel, zinc). Ferrous metals tend to rust more easily, so choosing a primer with a rust-resistant quality is a must.
Step 1: Wipe the Surface
Take a clean cloth and wipe the surface to remove any loose dirt and debris.
Step 2: Remove Old Paint and Rust
If your metal surface is already painted or rusty, use sandpaper or a wire brush to remove the old paint and any rust. For new, unblemished metal, use a fine-grit sandpaper to rough up the surface. This helps the primer stick better.
Wear a respirator, safety goggles and gloves and work in a well-ventilated space when working on metal.
Step 3: Repair Cracks and Holes
Fill in any cracks or holes with a filler suited for metal surfaces. Sand those areas smooth.
Step 4: Clean the Surface
Use a rag and a degreaser, mineral spirits or acetone to clean the metal. Rinse with water to remove any residue from the cleaning solution. Be sure to wear gloves and a mask or respirator for protection.
Step 5: Apply the Primer
Use a primer that’s suited for metal surfaces. One that inhibits rust is ideal, especially if your metal surface is susceptible to rust.
Stir the primer and pour it into a paint tray. Apply the primer using a brush or a roller. Refer to the manufacturer instructions for dry times.
Once the primer is dry, the surface is ready for paint.
For some projects, such as painting wrought iron patio furniture, brushes and rollers may not be the best tool for applying primer. Instead, a spray primer can easily coat intricate details and surfaces that are too small for a brush or roller.
Priming Drywall FAQ
Here are some common questions about how to prime drywall that may help you make the best decision for your paint project.
Do I Really Need to Prime Drywall Before Painting?
It’s always a good idea to begin a painting project with primer, especially if you’re painting new drywall. Primer seals the surface, so your paint looks consistent and is free of blotchy or dull spots where paint may have been absorbed unevenly otherwise.
Can I Skip Primer if I Use Paint-and-Primer-in-One?
Yes, but it’s not recommended for new drywall. For raw drywall, a dedicated primer is best. For previously painted walls, a paint-and-primer-in-one is typically okay to use. But if you’re making any repairs to the wall beforehand, switching from a dark color to a light one or covering stains, a base coat of primer is best.
How Many Coats of Primer Do I Need?
One coat is usually enough for new drywall. Porous, heavily patched and stained surfaces may require a second coat, as well as walls that are drastically changing color.
Do I Need to Sand Drywall Before Priming?
Lightly sanding your walls before priming is recommended to smooth out any joint compound or other imperfections. Be sure to wipe off dust with a damp cloth or tack cloth afterwards.
Should I Prime the Entire Wall or Just Patched Areas?
Prime the entire surface for best results. Spot priming can cause flashing, an uneven sheen, when you paint. Not priming the wall at all can lead to uneven color or sheen, more paint absorption (which can cost you more) and visible patches or seams.