What finish can be applied over polyurethane?

You can apply oil-based or water-based finishes over polyurethane, but it's essential to ensure proper adhesion. A compatible finish, such as a gel stain or a topcoat specifically designed for use over polyurethane, is recommended. Prior to application, lightly scuff-sand the polyurethane surface to create a better bond. Always test the finish in a small area first to ensure compatibility and desired results.