What Is Primer?

 If you’re repainting your home, you are probably wondering if you need to use primer paint. You may not even be sure what the difference between primer and regular paint is. Well, we’re here to help answer all your questions and explain why primer is so important in the painting process.

Paint primer is a critical first layer on any surface because it helps the topcoat adhere to the surface. The paint also lasts much longer with primer than without.

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WHAT IS PRIMER PAINT?

So how is primer different from regular paint? The simple answer is primer has a higher resin density than regular paint. These paints bind to the wall materials and create a smoother surface. The higher resin density also helps the topcoat paint – which has more pigment than primer – stick to the surface and adhere for a long time.

Using primer on a bare surface reduces paint failures like peeling and flaking, and it can block stains and odors that exist beneath the primer’s surface. Some of the benefits of primer include:

BENEFITS OF PRIMER

Use less paint – Some surfaces like wood are especially porous and will soak up paint. The primer serves as a buffer between the surface and the paint, and you will use less paint overall by applying it.

Helps paint adhere to surfaces (like vinyl/plastic) – Like we said before, primer has a higher resin density that paint will adhere to. This is particularly important on very smooth surfaces like vinyl and plastic that need the extra assistance to keep paint on the surface.

Paint lasts longer – Because of the improved adhesion, paint will last much longer on a surface without failing when you use primer.

WHEN TO USE PRIMER PAINT

Paint primer has a lot of paint benefits, but that doesn’t mean it is always necessary. However, primer isn’t always necessary. Here are some examples of times you should use primer:

WHEN TO USE PRIMER:

Porous surfaces: Porous surfaces like wood, bare drywall, and brick.

Drywall is skim-coated: A skim coat is thin layer of drywall spackle spread over a surface. Drywall compound is incredibly porous and will need primed before you can paint over it.

Previous coat glossy: The sheen on glossy surfaces is incredibly smooth, and paint is not going to stick well to that surface. Glossy surfaces need scuffing and a fresh primer over the surface to get maximum adhesion.

Going dark to light: If you plan on changing the color of the room significantly, namely going from a dark color to a light color, a primer is going to speed the process up. Lighter paint colors have trouble covering over darker ones and will require multiple coats to get full coverage.

Surface has stains: If the surface has stains, a primer will be necessary to prevent the stain from bleeding through the new coat of paint. This especially important for wood surfaces or any surface with clear nicotine stains.

WHEN YOU DON’T NEED TO USE PRIMER:

If the wall is already painted: If the surface is already painted, you usually don’t need to apply primer. The previous surface will serve the same purpose as a coat of primer.

The walls are clean (free of discoloration like nicotine stains): If there are no stains on the surface, you don’t need to apply primer. That’s assuming the surface has been primed and painted before. You will always want to prime wood surfaces to prevent tannin bleed-through.

If you are painting a similar color: Unlike when you paint from dark to light, you don’t need to prime if you are painting a similar (or the same) color as the original paint.

CAN YOU PRIME OVER WALLPAPER?

If you are having a hard time getting wallpaper glue off the wall, you can prime over it to prevent the glue from bleeding through. However, we don’t recommend painting over wallpaper even if you prime it. As the paint cures, it will contract and pull up the wallpaper at the seams. The only way to fix this is to remove the wallpaper and paint the wall again.

TYPES OF PRIMERS

There are several different types of primer on the market, and each are a little different depending on the base materials of of the paint formula. Here are the main types of primers you are likely to come across.

OIL-BASED PRIMER

Oil-based primers (and all oil-based paint products for that matter) are on their way out, so you likely won’t find them much anymore. That’s because they aren’t environmentally friendly and have a lot of VOCs. That being said, there are a few specific instances where oil-based primers can still be used.

Oil-based primers are great for sealing wood surfaces and preventing stains, so are a great option for painting trim and stairwell systems in stain conversions.

SHELLAC PRIMER

Shellac primer is the go-to alternative for oil-based primer because of its excellent stain-blocking qualities. This primer does have a very strong odor and high VOCs, though, so you will always want to wear a mask when applying it. It’s best to use this type of primer for specific jobs rather than as a general purpose primer.

ACRYLIC-LATEX PRIMER

Acrylic-latex (also called water based) formulas are the standard you will find in most paints and primers. They offer low-VOC (and often times no-VOC) products, making them a much more eco-friendly solution.

Latex primers also dry quickly, which makes them great for working quickly. However, they aren’t particularly well-formulated to block stains.

HOW TO USE PRIMER PAINT

PREP AREA

Before you ever begin painting, you will want to prep the surrounding area. This includes taking everything off the walls, moving breakable items out of the work area, and pushing any furniture into the center of the room.

You will also want to lay down plastic or drop clothes over anything you don’t want paint on. Next, tape off the area so you don’t get paint on the wrong surface.

Once the area is sufficiently prepped, you can begin working on the surface.

SAND THE SURFACE

Before you apply primer (or any coat of paint) you will want to sand first. Sanding scuffs the bottom layer and gives the primer a better grip on the surface. You will want to sand the entire surface that is getting painted.

If you are spot-priming, you only need to sand the area being primed for this step. You will sand the whole surface when it’s time to apply the top coat.

PRIME THE SURFACE

Once the surface is sanded, it’s time to prime. Generally, this means taking a brush and cutting in along the edges if you are painting interior walls. Then you will use a roller on the majority of the surface to spread the primer. 

In some instances, like in a new build or in an empty home, a sprayer may be used. If that’s the case, the primer will also need to be backrolled if applied on ceilings and walls. 

SAND AGAIN

Once you are done priming, you will want to sand again. This will give the top coat some abrasion to stick to, making the finish more durable for the long term.

HOW MANY COATS OF PRIMER DO YOU NEED?

When you apply any paint product you want to make sure the surface is fully covered, and that goes for primer as well. In general, that means you will want two coats of paint. If you are changing from a dark to light color, you may need more primer.

WHAT ABOUT SELF-PRIMING PAINT?

Self-priming paint (or paint and primer) is pushed a lot in DIY spaces, but by and large this is just marketing lingo. If a product is branded as a paint and primer, that really just means it is a premium top coat product.

You will always want to use a separate primer, even if the product markets itself as a paint and primer solution. Primer and top coat finishes have two different functions and therefore have different chemical makeups.

While you can use a self-priming paint as just that, it is not going to have the same longevity as a two-step prime and paint solution.

RECOMMENDED PRODUCTS:

Now that you know what primer is and why it’s important, here are some recommended products. These primers have different applications and need cases, and it’s always important to find the right product for the job.

SHOULD I PAINT MY HOUSE DIY OR HIRE A PROFESSIONAL PAINTER?

For the best results, it’s definitely worth investing in a professional to paint your home interior or exterior. Painting a project DIY may seem like the cheaper option, but once you factor in the cost of materials and the time lost working on the project, you may end up spending a lot more than you would simply hiring someone.

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