A strange thing happens to people when they’re getting ready to paint. They’ll go to the paint store and run through the mental checklist of everything they need like brushes and rollers. They’ll pick up a quality paint (or two), and then someone who works at the paint store will ask, “Do you need primer today?”
In that instance, a flood of decisions usually results in someone saying, “Nah. Not today.”
In their mind the assumption is, “If I just paint on more than one coat it should be fine.” That glomming on 3 or 4 paint coats is easier, faster, or cheaper than just the one coat of primer.
Primer isn’t necessary in every paint job. But it is essential when you have:
- Bare wood, unfinished wood, or wood paneling
- A surface with prior mold or mildew stains
- A new surface, like drywall
- Interior walls in damp or challenging environments
- Metal, particularly when it’s exposed to open air or moisture
To understand why primer is necessary, we need to know how and why primer works the way it does, and no matter how many coats of paint you roll on, that first coat of primer is critical.
5 ways primer prepares a surface for your painting project
Primer coats a surface and is designed to do five things:
- Primer coats a surface and forms a seal. This is vital for wood, drywall, and masonry (like bricks) because you don’t want the paint to seep into bare wood or masonry. You want to layer it on evenly and smoothly.
Many surfaces act like a sponge, absorbing paint and creating uneven surfaces that no amount of additional paint can fix.
- Primer helps paint adhere to the surface with specially-designed binding agents. In high-moisture or high-traffic areas, a quality primer with quality paint can double or even triple the life of the color. Paint will bubble, chip, crack, or fall off the wall without primer.
- Primer ensures color uniformity and color matching. On wood paneling, as one example, you may have lighter and much darker colors in the wood. On bare wood you might see knots that create dark spots in otherwise lighter color areas. Primer coats these areas and fixes them all, ensuring that your white paint or color of choice rolls on as you intended.
- Primer can smooth out small cracks, holes, and textures. The most common is a dimpled wall or ceiling where, short of sanding the walls down, a quality primer coat can quickly smooth the surface.
- Primer improves the durability of the surface and the paint. Primer is like an undershirt that helps protect against wind, rain, and temperatures that can degrade the substrate surface.
Differences between metal primer, masonry primer, and more
There are several different kinds of primer and they work well for the surfaces they’re intended for.
Metal primer protects metal
No surprise here; metal primer is for use on metal. This includes aluminum, steel, and iron.
If you were painting a metal fence or grate, you’d reach for a metal primer. Metal primers prevent rust and corrosion, promote adhesion between the paint and the surface, and can even help protect against UV light because of their zinc-derived properties.
Rusty metal can benefit from a metal primer, too. Just lightly sand the metal to remove the chips and flakes before applying it.
Masonry primer is designed for porous surfaces
Bricks, concrete blocks, cement, and other masonry surfaces are highly porous. You don’t even need a microscope to see how many holes are in there. This gives masonry a lot of unique properties, such as the ability to reflect and absorb heat. But it means you’ll need a masonry primer to get an even, uniform finish. Without it, paint can exhibit peeling, efflorescence (the migration of salt to the surface), and degrade its lifespan.
Stain-blocking primer protects against mold and mildew
Stain-blocking primer is best used where previously painted surfaces have mold or mildew damage, but they’re also great for use where smoke, tobacco stains, watermarks, or fire damage has been a problem.
Stain-blocking primers are not invisibility shields. You should never paint over active mold or mildew with a primer. That poses a health risk for others later because it doesn’t kill the mold; it just hides it for a while.
Tinted primer helps paint appear more vibrant
Tinted primer has a little color added to it, usually some shade of a base gray or some neutral color. Tinted primer helps establish a “base color” across a surface, like if you’re painting a wall that previously displayed a mural or a mix of dark color and lighter color.
Most people usually don’t need a tinted primer, and the standard white primer is fine. If you’re unsure, ask a professional painter or someone at the store.
What about self-priming paint? Do I need a primer if I use that?
Self-priming paints work well in small areas or areas that are otherwise in good condition. They have many of the generic properties of primer, but if you’re painting something outdoors or need to paint bare wood or masonry, use the recommended primer for the job.
If, like on an indoor wall, you want to use self-priming paints, always use two or more coats.
You’ll still use two coats of paint
Somehow, people like to imagine they can save time, money, or both by not using a second coat of anything. But, like paint, you might have surfaces that warrant a second coat of primer and two coats of paint.
Yes, that’s four layers, but some surfaces demand it, particularly if you’re dealing with rough surfaces, old paint, or planning on a very light color on top of a dark paint color or vice versa.
90% of the time you’ll be able to use fewer coats of paint if you use just one coat of primer. You’ll get better results, it’ll look smoother, last longer, cost less (in time and excess paint, or, worse: having to redo a paint job).
Skip the paint store and get it done quickly and reliably with Woodiwiss Painting
If using a primer feels like extra work and you just don’t want to do it, don’t! Give the professional paint crews at Woodiwiss Painting a call or send us a message.
Tell us what you’re preparing to do and we’ll do the work of sanding, smoothing, priming, and painting for you.