How to seal a gap under a glass door
Gaps under glass doors let in pests like spiders and leave openings vulnerable to leaks. Standard fixes like caulk are difficult to line up neatly, making it hard to seal the opening without ruining the appearance.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Using caulk along the bottomDid this help you?
- 2Replacing the door sweep at the bottom of the doorDid this help you?
- 3Caulk itDid this help you?
- 4installing a quarter roundDid this help you?
- 5using a cove moldingDid this help you?
- 6adding a transition stripDid this help you?
- 7using backer rod and caulkDid this help you?
- 8applying low-expansion window and door foamDid this help you?
- 9adding a small piece of trim like base shoe or window stopDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Freshly installed doors left a 0,5 cm gap between the threshold and building stairwell. How do i fill the gap so it doesnt leak and look somewhat acceptable?”source ↗
“Thanks so much i need to google that. Might go with a quarter round as another person stated”source ↗
“this area where the French doors are located is driving me crazy, idk if maybe it’s the flooring cuts or does there need to be one of those transition strips here?”source ↗
“i’ve caulked the interior frames (less than 1/8” gaps), over the screws in the jams, and on 3 sides of the exterior frames (leaving the bottom open) with quad max OSI. but one window has a larger gap on the bottom”source ↗
“do i just need a backer rod? non-expanding foam? i live in the pnw so i want to be super meticulous about the sealant because we get so much rain.”source ↗
“Just bought a new exterior door to replace a bad one and when I got it home and looked it over I noticed that the sill / threshold had this gap, same on other side just not as bad is this normal and should it be siliconed after door is installed?”source ↗