You’re Painting Latex-Based Paint Over Oil-Based
You know the saying that oil and water don’t mix? Well, the adage holds true for paint. Latex paint, which is water-based, won't adhere well to a wall that's already been covered in oil-based paint—unless you prime first.
You’re Painting Over a Skim Coat
A skim coat is a thin layer of plaster or drywall compound that’s applied to smooth out the surface of a wall. This material is porous, which means it soaks up a lot of paint. To reduce the amount of paint required to cover the wall evenly, you should always prime a skim coated surface before applying color to the wall.
You’re Painting Over Unfinished Wood
Bare wood is among the trickiest materials to paint. The natural fibers in the wood absorb a lot of paint, and variations in the wood grain can create an uneven finish. So, for the best results, always prime before you paint unfinished wood.
You’re Painting Over a Darker Color
Dark interior paint colors have been all the rage in recent years but when the trends change, you'll want a coat of primer. Painting a light color over a dark color requires additional coats of paint to keep the old color from showing through the new shade. You can cut down on your work (and your costs) by priming the wall before you paint.
You’re Painting Over Wallpaper
Yes—in fact, you can paint over wallpaper. But you shouldn’t attempt it without priming first. On the other hand, if you’ve already removed the wallpaper, you need to prime the wall to correct any nicks or flaws sustained in the wallpaper removal process, in order to achieve the smoothest final finish possible.
You’re Painting Brand New Drywall
Fresh drywall soaks up paint like a sponge, and the mudded joints take paint differently than the bare drywall between the joints. Translation? Without a coat of primer, you're looking at a splotchy paint job. Applying primer prior to painting drywall will give your finished wall an even, clean look.
You’re Painting Masonry
Masonry and brick are very porous surfaces and soak up lots of paint. On top of that, masonry surfaces have a high pH, which makes it difficult for paint to adhere. So, it’s best to prime masonry or brick prior to painting it.
You’re Painting a Surface That’s Stained
Clever project ideas and step-by-step tutorials delivered right to your inbox each and every Saturday morning—sign up today for the Weekend DIY Club newsletter!