When painting exterior wood, some people recommend caulk to keep moisture out of the wood; others say you should 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 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. Caulking where the siding overlaps is not advisable, as it could trap moisture behind the paint, causing it to peel.
