Sealing a gap under a garage door
Homeowners discovering a gap beneath their garage door that allows pests or water to enter due to settling or missing seals.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 34.9× more often in r/homeowners than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1installing a new rubber bottom seal on the garage door
- 2adding a threshold seal kit to the floor
- 3hiring contractors for concrete lifting or slab jacking
- 4riding it out without fixing the underlying structural shift
- 5Clean out the gap, insert a backer rod with sand, and finish with a self-leveling sealant.
- 6Clean the gap and fill it using hydraulic cement.
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Have this gap at the bottom of my garage door. Exterminator said he was surprised i haven’t been having a mouse problem but ive only been living here about 2 weeks so its not too late to get one :) Any tips to fill this space before that happens?”source ↗
“I went through this recently, mine wasn't this bad but water was getting under it when it rained. New bottom seal on the door, and a threshold seal on the floor did the job quite nicely.”source ↗
“Garage is sinking. Mine is doing the same thing. I’m just riding it out.”source ↗
“The gap between our garage and driveway is all crumbled and missing bits of concrete and I want to fix it before winter.”source ↗