We may earn revenue from the products available on this page and participate in affiliate programs. Learn More › No matter how skilled you are with a paint brush and roller, painting water-based paint over oil-based paint without intervention and proper preparation is a problem waiting to happen. Because water-based paint isn’t able to adhere to oil-based paint, you may see cracking, peeling, or even sheeting off of the paint, even if it feels dry.  The good news is that it’s pretty easy to test a surface and determine if there’s oil-based paint on it—and the simple methods below require nothing more than common household supplies. 1. Do a scratch test. Photo: Tom Fenenga for BobVila.com Water-based paint Paint brush While the scratch test doesn’t provide an immediate result, it only requires water-based paint and a paint brush. And you just have to wait until the paint is dry—just a few hours or overnight—to test it. Here’s how to test for oil-based paint.…