How to Tell the Difference Between Oil-Based & Latex Paint on Trim

Before painting over trim, determine whether the existing paint is oil-based or latex.

Oil-based and latex are the two most commonly used types of paint in the home, and before you repaint any trim you must be aware of which type you are dealing with. Paint is a protective film, and choosing the right type of paint ensures not only that you achieve the desired finish, but also have proper protection for the surface to offer maximum performance. Determining whether you are painting over oil or latex paint ensures that you choose a compatible paint; oil and water are incompatible, and applying one type over the other will prevent the paint from sticking.

Instructions

1. Break a small piece of paint off the old trim.

2. Hold the paint chip between your fingers with two hands.

3. Bend the paint chip in half. Oil paint is brittle and latex paint flexible. If the paint breaks cleanly in half, it is oil-based paint; if it bends more easily and takes more effort to break, you are probably dealing with latex paint.

Tips & Warnings

• Paint and hardware stores carry products such as latex solvents, which can be applied over top of an area of the old trim; if the paint starts to bubble, it is latex.

References

• House Painting Info: Choose the Best House Paint for Your Project
• Fine Home Building: Repainting Interior Trim