Windows discussions and local services.
Discussion options
Should a gap at the bottom of window trim stay open?
A small gap where exterior window trim meets siding seems like it could be either a failed caulk joint or a place water is meant to drain. I’m not sure how to tell, especially when the reason for the gap isn’t obvious.
Does the joint’s location matter most? I’d be interested in what to look for at the top and sides versus the bottom, and whether the siding’s drainage details should be visible before deciding to caulk. Would staining or soft trim change the assessment, or suggest a flashing problem rather than a simple open joint?
Join the conversation
Share your experience or ask a follow-up question.
1 reply
At the bottom, the key is whether the gap is an outlet from the window’s drainage path. Some window and siding systems direct incidental water out at the sill, and sealing that outlet can trap water inside. A gap’s position alone doesn’t establish its purpose; check the window’s drainage details and how the siding is arranged before deciding to caulk it. If the opening isn’t part of a drainage path and leaves an exposed joint, sealing may be appropriate.