Garage Door Bottom Seal Replacement
The bottom seal is the barrier between the door and the floor. When it flattens, tears or freezes, water and cold air come straight in.
The bottom seal, or astragal, slides into a retainer along the bottom edge of the door and compresses against the floor when the door closes. It handles the toughest conditions on the whole door: standing water, ice, road salt tracked in by vehicles, and constant compression.
Uneven floors make the problem worse. A slab that has settled or a driveway apron that slopes can leave a persistent gap on one side even when the seal itself is intact.
Replacement includes inspecting the retainer, choosing a seal profile suited to the floor condition, and confirming that the door's closing position lets the seal compress evenly without over-compressing and holding the door up.
Common signs
- Water running under the closed door
- A visible gap at the floor line
- The seal is flattened, torn or missing sections
- Snow or leaves collecting inside the door
- The seal freezes to the floor in winter
- Rodents or insects entering under the door
Common causes
- Compression set from years of closing
- Ice bonding the seal to the slab and tearing it
- Road salt and moisture degrading the material
- An uneven or settled garage floor
- A damaged or corroded retainer
- Opener down-limit set too high or too low
Our inspection
- Inspect the seal and retainer along the full width
- Check the floor for slope, settling or damage
- Verify the door closes level to the floor
- Check opener down-limit setting
- Inspect the bottom section for damage
- Review threshold options if the floor is uneven
The process
- Measure width and identify the retainer profile
- Remove the old seal and clean the retainer
- Repair or replace a damaged retainer
- Install the correct seal profile
- Adjust the opener down-limit for even compression
- Test closing and confirm the gap is sealed
Risks of delaying service
- Water intrusion damages stored items and promotes rust
- Ice under the door can prevent full closing
- Salt-laden moisture accelerates hardware corrosion
- Gaps invite pests into the garage
Related components
- Bottom seal / astragal
- Bottom retainer
- Bottom section and brackets
- Threshold seal
- Opener down-limit setting
Where this service applies
Residential garages, especially those with sloped or settled slabs or doors exposed to standing water.
Frequently asked questions
- Why does water still come in with a new bottom seal?
- Usually the floor is uneven or slopes toward the garage. A different seal profile or a floor threshold is often the fix.
- Can the bottom seal freeze to the floor?
- Yes, and forcing the opener can tear the seal or strain the door. Freeing the ice first and replacing a damaged seal is the correct approach.
- Is the bottom seal the same as the weather stripping on the sides?
- No. The bottom seal sits in a retainer on the door itself; perimeter weather seal attaches to the jambs and header.