If you've purchased a piece of antique furniture or live in an older home, it is possible that the furniture or some of the wood surfaces in your home were painted with oil-based paint. Be sure to inspect your doors, cabinets, molding, trim, or any other woodwork done in your home. Though most paints used in homes are water-based latex formulas, it is always a good idea to run a test and determine if the paint is oil-based or not. In the end, it will save you time, money, and elbow grease! 

Figure 1. In this photo, blue latex paint has been painted ontop of white oil-based paint. As a result, the fresh coat of blue latex paint is peeling off the walls. Be sure to test what paint type has been previously applied to a surface before painting.

Take the test!

As you can see, if you make the mistake of painting latex paint over oil-based paint, the paint will become splotchy and flake off. Sometimes you can tell if a paint is oil-based or not by the touch. Oil-based paint feels smoother to the touch. However, if you can’t tell, take this test!

Before painting, dip a cotton ball/pad or a cotton swab into a small amount of denatured alcohol. Rub the damp cotton ball/pad or cotton swab over a small area on the surface. If the paint does not rub off, it is oil-based paint and you will need to prime the surface. If the paint comes off, it is a water or latex-based paint and you can proceed by painting over the surface with any type of paint. Here are your next steps:

It didn’t rub off, it must be oil-based paint!

If the paint does not rub off, it is oil-based paint and you will need to prime the surface with a bonding primer before applying a coat of latex paint. Once the primer coats are dry, you can then successfully use latex paint (Not sure of what brushes to use? We can help)

Pro Tip: The primer can be a latex formula, however, be sure that the product is specifically for preparing the surface and helping with paint adhesion. These products are labelled as “bonding primers.”

It rubbed off, it must be water or latex-based paint! 

If the paint comes off, it is a water or latex-based paint and you can proceed by painting over the surface with any type of paint.

Pro Tip: If you are unsure of what paint finish to use, here is your guide

What about painting over stained wood?

If you are painting over stained wood, you need to use a stain-blocking primer. If you skip this step, your painted finish will start to get a brown tinge in areas where the tannins in the wood seep through.