What Is Primer (& Is It Necessary)?

You’re probably aware that using a primer before painting is generally a good idea. But is primer always necessary?

In most cases, yes, you’ll want to use a coat or two of primer before painting. It might feel like primer is an unnecessary step in the process that takes extra time and costs more money, but the benefits of using a primer far outweigh those inconveniences.

As a rule of thumb, you should always prime before painting:

A brand new, unpainted surface
A porous material
Over a different color
With a flat finish over a glossier finish
Over a worn-down surface

Priming makes your task easier in the long term by reducing the number of coats of paint you’ll need and protecting your paint from wear over time. With primer, you can achieve a professional-looking finish regardless of your skill level.

What Is Primer?

Primer is the first layer of paint applied to a surface before it is painted. It acts as a buffer between the naked surface and the color by “priming” the surface to be painted. Primers are made up of three components: synthetic resin, solvent, and an additional agent. Primers are typically white, though some are colored.

When used correctly, a primer will:

Cover flaws in your wall, such as patched or mended sections.
Prevent stains from bleeding through your freshly painted finish.
Create a smooth surface for your paint to adhere to.
Provide a consistent base for a smooth, seamless paint application.
Neutralize the color of your surface, allowing the most accurate, most brilliant color to shine through when new paint is applied.

Paint vs. Primer

While paint and primer look similar, the two have several key differences. Unfortunately, those differences mean you can’t just buy a can of white paint and get the same benefits as using a primer.

While paint and primer are identical in many ways, their chemical composition distinguishes them. Paints are pigment-based, whereas primers are resin-based. This is important because resin allows the primer to infiltrate the pores of a surface and fill them. As a result, priming serves as a sealer and gives you a better surface to paint on. Paint pigments do not have this characteristic; instead, they provide color and durability.

Some products market themselves as “self-priming paint.” These products combine paint and primer in one application and are a convenient way to kill two birds with one stone. While self-priming paints can work great in some applications, they are not a good option for all surfaces. A good quality self-priming paint with a high-caliber resin should work out fine for drywall applications, but not so much on metal or certain types of wood.

When Should You Use Paint Primer?

You should always use a primer before your two layers of paint. The primer will help you achieve that professional-looking finish we all want.

Priming allows for the richest, most true color to show through. It’s what we refer to as the “ideal base for spectacular color.” In most cases, one coat of primer should be enough, but in the following situations, two coats of priming are required:

When transitioning from a high-sheen to a low-sheen finish, such as semi-gloss to eggshell.
Transitioning from a dark color to a lighter color.
If you’re painting in a humid place, such as a bathroom, where mildew and leaching are more likely.
If you want to cover up stains on your wall (like water spots from a bathroom leak or smoke damage from a fire in a kitchen).
When applying paint to unpainted wood trim or other porous surfaces.

Types of Primer

There are three main types of different paint primers to choose from. Make sure you select the correct primer based on the project you are working on.

Oil Based Primer

If you are working with latex or oil-based paint, you’ll want to reach for a can of oil-based primer. Oil-based primers can be used on several different types of surfaces, withstand the elements, and are excellent at covering up old stains and resisting new ones. However, it takes a full 24 hours for oil-based primers to dry, and have strict rules on how to dispose of them safely.

Oil-based primers work great on raw wood and drywall, which can be very porous and soak up a lot of primer. Oil-based primers are also great for stained and damaged surfaces or walls that have been patched.

Latex Primer

Latex or acrylic primers are great for situations where you need a thin layer of primer to be applied quickly. Latex primers are water-based, which makes them safer and helps allow for those thin layers. They also have a very quick dry time, needing just 3-4 hours before you can start applying layers of paint. The thin layers do have a drawback, allowing stains to show through more clearly.

Latex primers are ideal for drywall, masonry, concrete, metal, and some types of wood. Always test your primer on wood, as it could cause the grain of the wood to rise, which would ruin your finish.

Shellac Primer

Shellac primer has been around for centuries and still is a popular choice. One of the biggest reasons to use a shellac primer is its quick drying time. Shellac primer can dry in less than an hour, reducing downtime and speeding up the painting process. Shellac primer is also great at blocking stains, just like oil-based primers. The biggest drawbacks to shellac primer are that you must thin it with denatured alcohol, and the fumes from the primer mean you should always use it in a well-ventilated space.

While you can use shellac primer on a wide variety of surfaces, it is designed only to be used with oil or latex paint. So make sure your paint is compatible with this before grabbing a can.

Professional Paint Jobs Start With Primer

A new paint job is a relatively easy way to transform the look of your home—inside and out.

But after all the time and effort of choosing a color, taping off the room, putting down tarps, and covering all the walls, take the time to ensure the job is done right. Primer is more than an aspirational ideal. It makes the job easier and lasts longer.

Use the right primer if you’re looking for a fantastic paint job. If you’re looking for a professional paint job, hire a pro!

At Scott McDonald Painting, we aim to ensure that your home or business looks fantastic. We are committed to quality work and attention to detail that you won’t find anywhere else. We have a wide range of residential and commercial services, and we can even help you decide on a good color scheme with our color consultation.