How to Cover Oil-Based Paint With Latex Paint

Conventional wisdom says you can't apply latex paint on top of oil (alkyd) paint, and if your walls were originally painted with oil paint, you will need to use oil paint when you want to repaint. Supposedly, the surface of the oil paint is just too slippery and doesn't provide enough of a "tooth" for the latex paint to adhere. The end result is a painted surface that cracks, scratches or peels easily (and basically looks like heck).

However, if you don't like the idea of having to use oil paint (with its messy cleanups and unpleasant odors) you can actually apply latex paint on top of the oil paint, and it will stay in place. The trick is proper preparation before you start to paint. Here's how you to prepare your walls so you can put latex paint on top of that old oil paint.

Things You'll Need

• Acetone or denatured alcohol
• Cotton swab
• Sandpaper (100 grit) or liquid sandpaper
• TSP (trisodium phosphate)
• Primer (oil based or acrylic)
• Painting supplies such as brushes and rollers
• Drop cloths

Instructions

1. Run your hands over the paint surface. Oil paint usually feels smoother than latex paint (which has an almost rubbery feel), and it generally has a glossy or semigloss finish.

2. Still not sure? Use a cotton swab dipped in acetone or denatured alcohol. If the paint is oil based, nothing will happen, but if the paint is latex, some color will come off on the cotton swab and the area will feel tacky.

3. Once you know your walls have oil paint, you need to prepare the room for painting. Clean out the room and spread drop cloths around the perimeter.

4. Using 100-grit sandpaper, go over the entire wall surface (you need to rough up the surface to create the "tooth" so the latex paint will stick on the walls).

5. After sanding, wash the walls with trisodium phosphate and water. This will get rid of any sanding dust on the surface and ensure the walls are clean.

6. Once the walls are dry, apply a coat of a good oil-based primer.

7. After the primer has dried, apply your latex paint. You will probably want to apply two coats to ensure your newly painted walls end up the color you choose.

Tips & Warnings

• You can buy test kits at paint and home stores to test whether your walls are painted with oil or latex.

• Liquid sandpaper (also called "paint deglosser") is an alternative to sanding your walls.

• Some folks suggest you can use nail polish remover and a cotton swab to test for oil paint. The problem is, not all nail polish removers contain acetone, and you could end up with an incorrect result.