Answers to pro painters’ most pressing questions by Rick Watson

I hear conflicting advice for painting exterior wood. Some recommend caulking to keep moisture out of the wood. Others say to leave gaps to allow the house to breathe. Which is right?

Both ideas are correct. Since moisture is the culprit in many cases of exterior peeling, it’s important to use a good quality acrylic caulk to fill gaps around windows and doors, joints in siding and trim boards, and anywhere moisture could get into the end-grain wood.

However, you also need to make sure that moisture generated inside the house has a way to escape. The best way to allow a house to breathe is with gable, roof, and eave vents.

If you are correcting an existing moisture-related peeling problem, you may also need to install siding wedges or vents to give the moisture an easier path of escape than through the paint film. It’s not advisable to caulk where the siding overlaps, as it could trap moisture behind the paint, causing it to peel.

This article was published in the Spring 2019 issue of PPC magazine. Rick Watson, director of Product Information and Technical Services at Sherwin-Williams, answers questions from pro painters in the Ask Your ProPartner™ column in PPC magazine.

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