Advice on Repainting Water-Damaged Wood, from Jim Avery at Precision Painting of Westchester in White Plains, NY
I live in an older apartment and my wooden windowsills have been swelling with all the humidity we’ve had this summer. I've been keeping the windows closed so the sills don't get wet during thunderstorms, but the wood is buckling so much that the white paint is all cracked. Do I have any hope of getting them to stop plumping up, or of fixing the paint without stripping it first? — P.L., Elmsford
Hurricane Irene stormed through shortly before I tackled your inquiry, so I’d guess your sills recently underwent an epic plumping-up. Wood that’s swelling is absorbing moisture, so you need to rectify that problem first. Paint is essentially a skin that protects surfaces, so it’s possible that your cracked paint is allowing moisture in, rather than being the result of dampness.
In any case, “there’s no quick remedy with paint and moisture — they repel each other,” says Jim Avery at Precision Painting of Westchester in White Plains (914-761-4971). Avery immediately went on high alert about possible lead in your paint, which will probably be peeling before long. “Right out of the gate, if that apartment was built before 1978, he needs to find out if the material has lead,” he says. “Lead is a big deal; it’s very dangerous.” Avery suggests calling in a professional to test the paint, although there are kits available in paint stores if you want to do the test yourself. Those approved by the EPA are the most reliable.
“I’d push anybody who finds lead to get a person who’s certified” to handle the prepping and repainting once the wood is completely dry, Avery says. If you’re a do-it-yourselfer, he recommends these precautions: “Wear a white Tyvec jumpsuit that covers your whole body, goggles, a mask with a HEPA filter system, and gloves.” It sounds a little over the top to repaint a couple of window sills, but Avery says he takes the presence of lead “very seriously indeed — especially if there are children around. If a child is exposed, it causes damage that’s irreversible.”
If there’s no lead problem, you can prep and repaint wearing anything you like. Again, be sure the wood is completely dry. You don’t have to strip the paint, but you need to scrape off any that’s loose. “Then use a patching material to create a smooth surface, and sand it down. DAP makes a good-quality interior patch for trim,” Avery says.
As you’ve had a moisture problem, Avery recommends an oil primer as a base coat. “I’d suggest Benjamin Moore’s Alkyd Enamel Underbody primer. For a top coat, Benjamin Moore’s Satin Impervo is low-luster with a very hard finish, although the white can yellow over time,” Avery adds. If you prefer a latex top coat, he says Benjamin Moore Aqua Glo is the best choice, and can be used over an oil-based primer.