Oil-based paint once ruled the world of interior paint and coatings, particularly in high-impact areas such as trim work, doors, and cabinets. Yet no longer. When it dries, oil-based paint emits a host of VOCs (volatile organic content) that are harmful to the environment. On an individual level, homeowners often find oil-based paint's clean up procedures messy and smelly since mineral spirits or paint thinner must be used, not water.
With the nearly total phase-out of oil-based paint in the U.S. in 2005, the question of whether you can paint latex over oil-based paint is even more perplexing. If a house is old enough, it is inevitable that it will have oil-based paint somewhere since latex paint wasn't introduced until the 1940s. And newer houses might have some areas of oil-based paint since it is not entirely banned: Oil-based paint is still available in quart sizes or smaller. Many professional painters even favor oil over latex for a smoother, rock-hard finish.
Can You Paint Over Oil-Based Paint?
Latex or oil-based paint can be successfully applied over oil-based paint. As long as the surface is fully cured, there is nothing inherent in the oil-based paint coating that precludes an additional layer of latex or oil-based paint.
As with water-based latex paints using water as a delivery vehicle, oil-based paints use the oil as a delivery vehicle for the pigments and coatings. While oil-based paints are initially pungent and oily to the touch, this goes away after a day or two. By the time the paint is fully dry, there is no oil present in the surface: It has completely cured.
Preparation is important. Glossy surfaces will not take a second layer of paint well, so they need cleaning, sanding, and additional cleaning with a damp cloth or a tack cloth. Use a primer before putting down the latex paint. While advisable for many painting projects, a primer is a requirement for this one. If you have multiple layers of oil-based paint, consider scraping off the paint first.
Surfaces Typically Coated in Oil-Based Paint
How can you determine which surfaces in your house are coated in oil-based paint? After enough time has passed, you can no longer identify oil-based paint by its odor or by touch.
Oil-based paint is considered to be self-leveling. After the brush delivers the paint, the paint levels flat, leaving zero brush marks, gaps, bubbles, or holes. Door frames or window sills painted in an oil-based paint can be a beauty to behold, a near-museum piece that is glass-smooth and rock-hard. So, think in terms of areas that need durable, smooth coatings, such as:
How to Paint Over Oil-Based Paint
Applying latex paint over oil-based paint has less to do with the lower coat being oil-based than with the fact that this is a paint-over-paint project. Additionally, since oil-based paints tend to have a glossy sheen, it follows that the biggest issue to deal with will be glossiness, not the paint's base content.
Even when using similar types of paint, it is difficult to achieve the same adhesion as you would by laying down paint on primed wood. As a result, this project is mostly about preparation. Once the surface is adequately prepared, it is a simple matter to paint the material.
- Working Time: 1 hour for approximately 10 square feet
- Total Time: 1 hour
- Skill Level: Beginner
- Materials Cost: $20 to $60
Tools and Supplies You Will Need
- High-quality paint brush
- TSP (trisodium phosphate)
- Putty knife or five-in-one tool
- Wood putty or wood filler
- Tack cloth
Scuff the Surface to Remove Gloss
With fine grit sandpaper, scuff down the surface of the oil-based paint layer for improved stickability. Aim for eliminating surface sheen, or gloss. Gloss is as much an enemy of paint adhesion as is dirt. Pry off any loose paint with a five-in-one tool or putty knife. Fill small gaps and holes with wood putty or wood filler.
Damp-Clean to Remove Debris
Many layers of dust and dirt may compromise latex paint's ability to stick. While some latex-over-latex projects may allow you to bypass cleaning, this project is different and requires deep cleaning. You will need to build drying time into the project if using a damp cloth.
Easily available and inexpensive, TSP should be added to the water to improve its cleaning qualities. TSP is available in most hardware and home improvement stores and easily mixes with hot water. After cleaning with TSP, let the damp surface thoroughly dry.
Dry Clean With Tack Cloth
After the surface is completely dry, use a tack cloth to lightly wipe down the surface. Tack cloth is an inexpensive, simple product made of cheesecloth impregnated with beeswax. Its sticky surface is perfect for taking up those last stray motes of dust. Do not rub too hard. Applying hard pressure will result in leaving wax on the surface, which can be harder to remove than dirt.
Paint the Surface
With the surface completely dry and clean of dirt, you can now paint it as you would any other surface. Use a high-quality paint brush for best results.
Do not load up the brush with too much paint; only dip the tip of the bristles into the paint. Draw the paint in slow, even strokes, always maintaining a wet edge.
After at least two hours' drying time, paint the surface a second time.