Before you can put paint over a surface, you must have applied enough coats of primer first to allow the paint to sit nicely. So how many coats do you need?
You need 1-3 coats of primer on a surface before you can paint over it. However, the number of coats depends on the surface type, the color of the paint, and the brand.
Surfaces that are perfect (have no imperfections), don’t require too much coats. On the other hand, surfaces riddled with imperfections require more coats to cover the imperfections or holes it has.
Why Does it Matter?
The number of coats matters for primers because it determines how well it will cover (or seal) the surface. If you add fewer layers, the basecoat won’t cover the surface and imperfections properly. This will affect the quality of the finish.
If you apply too many layers, the primer coating will become too thick. This affects its dry time and makes its surface uneven — some parts will dry while the others will remain wet. Its coating will be also prone to cracks and bubble formation and might peel off because it was too thick.
Also, applying fewer coats means the basecoat will be prone to bleed-through. This means if the surface is already painted, and you apply only one thin coat of primer, the paint underneath will bleed-through and stain the coating. So, the existing finish and the grease and oils will affect the color and quality of the finish.
However, sometimes you can get away with fewer layers. For instance, if you are painting over a smooth and non-porous surface, one layer of basecoat is enough.
You need one coat if:
Using Paint & Primer in One
The paint & primer product has both, paint and primer in its formula. So, you need only 1 coat of it. However, if you are painting over a dark color or a surface with a lot of holes, then you might need a second coat.
Painting Over Light Colors
If you are painting over light colors, then you only need 1 layer of primer. If you are painting over white or grey color, then you can use a basecoat of the same color and paint over it. Light colors don’t have a lot of pigments so the paint won’t bleed-through.
Painting Over Old Paint
If you are painting over old paint (with the same color) then you only need 1 layer of basecoat. The paint has already filled all the holes in the surface and has the same color as the new paint.
The best way to know if you need a second layer of primer is to check the instructions on the container. The number of required layers will be indicated on the container or user’s guide.
You can also know if you need an extra layer by inspecting the finish. If the finish is rough, heavily colored, and hasn’t properly covered the full surface, you need another layer.
Here are some other cases:
Moist, Stained, Or Filthy Surface
When you are painting over a surface that is wet, stained, or filthy, you’ll need at least two coats of primer to properly block the moisture and stains from affecting the finish.
Dark or Bright Colors
For dark finishes, you need two layers of basecoat to properly cover it. That’s because dark colors are usually deep and difficult to cover with one layer only.
For bright finishes, such as green, red, or orange, you need two coats of basecoat to cover them because these colors can easily bleed-through.
Tip: To cover dark paints, use a grey primer.
Porous surfaces, such as wood, absorb more liquid than needed. So, you must properly seal them to prevent them from over-absorbing paint. So, you need to apply two coats of primer over the porous surface to properly seal them.
For surfaces that have just been repaired, you must apply two layers of primer to seal the imperfections and holes in the surface.
Also, it’s common to use concrete paste, caulk, polish, wood filler, and the likes on surfaces while repairing them. These compounds contain chemicals that can bleed-through and affect the finish. So you surely need more than one layer of basecoat.
Old or Fresh Wood
Old wood or furniture will most likely be affected by pests like termites and bugs. These pests would have damaged the wood by biting and drilling holes in the wood. So you’ll need at least two layers of primer to cover these holes or imperfections.
Also, fresh wood usually contains tannins and oils that can bleed-through and affect the finish. So you need at least two to three layers of a stain-blocking and moisture-resistant primer.
You need 1-2 coats of primer when painting over a light color, such as white or ash. This is because light colors are not heavily pigmented so it’s easier to cover them with just one coat. Also, light colors are neutral which means they won’t affect the color of the finish.
For dark or heavily pigmented finishes, you’ll have two to three layers of primer. This is because dark colors are usually deep and they contain more paint pigments than light paints. As such, it’s more difficult to cover the color or prevent it from bleeding through the finish.
If the surface is defective, moist, or stained, you’ll need to repair it first. Without doing that, you’ll need many coats of primer to first seal the imperfections on the surface and then more coats to cover the dark paint. This will cause you to apply too many coats and ruin the finish.
For bright or vibrant colors, such as red, yellow, or orange, you need at least two layers of basecoat. This is because these paints contain a high volume of paint colorants which produces a bright finish. So you’ll need more layers of basecoat to cover and prevent the bright color from showing underneath the finish.
If you are painting over a surface with the same color shade, you need one coat only.
Related Read: What Primer Color Should You Use?
Different Types of Surfaces
Let’s check some different surfaces:
On wood, you need at least 2 coats of primer. This is because wood is usually porous meaning it absorbs too much paint. So, you need to seal it properly to prevent over-absorption.
If the wooden surface is damaged, you need 3 coats. This is because the surface will be riddled with cracks, holes, and stains that can affect or bleed-through the finish. So, you must seal them properly.
For drywalls, you need at least two layers of primer. This is because drywalls are porous, so the first coat will be absorbed by the drywall. So, you need a second coat to properly seal the imperfections on the surface.
For fresh drywalls, you might need more than 2 coats, especially if the surface is wet.
For outdoor metal, apply two coats of spray primer since the surface will be exposed to weather elements. The spray primer will prevent oxidization on the metal surface which can cause rust.
For indoor metal surfaces, you need one layer of primer only. If the metal already contains compounds that prevent oxidization, you don’t need to apply a basecoat.
You need two layers of thick primer on kitchen cabinets. This is because kitchen cabinets are usually exposed to moisture, steam, heat, and constant friction or handling. All of this can ruin the wood so it needs enough protection.
For MDF and other furniture, apply just one layer of basecoat. This is because these items are usually placed indoors which means the surface is shielded from the elements. Also, MDF is not heavily used so it doesn’t need much protection.
However, if the MDF is placed outdoors, you should apply two layers of basecoat.
On concrete, you need two coats of epoxy primer. This is because stone surfaces like concrete and masonry are usually rough and uneven. So, you need to properly cover the imperfections and create a smooth layer for the paint to stick to.
You’ll need a layer of primer on plastic. This is because plastic surfaces are non-porous meaning that paint can’t be sucked in. Also, plastic is a very smooth material meaning that the finish will come out smooth even without a basecoat.
In summary, the amount of primer coats depends largely on the surface, the type of prime, the type of existing and new finish, and the condition of the surface.
Tony is a professional painter and an author of DIY Geeks. Tony has completed over 1,000 painting projects for his clients. It's safe to say he knows what he Is talking about,