A garage door bottom seal is a strip of rubber or vinyl on the lowest panel that closes the gap to the slab. When it tears, flattens or lets in daylight, rain can run under the door. Replacing it is a job you can often do from the floor, but never touch the bottom brackets, springs or cables.
1What the bottom seal does
The bottom seal sits in a channel along the lowest panel. When the door closes, it presses on the slab and blocks water, leaves, drafts and pests. Clopay's inspection checklist lists tears or gaps in the bottom weather seal, and in the perimeter seal, among the things to look for on a monthly check.
2Signs the seal has failed
| What you see | What it likely means | What to do |
|---|---|---|
| Daylight along the bottom with the door shut | The seal is flat, worn or the slab is uneven | Replace the seal; check the slab |
| Water on the floor after rain | Gap at the seal, or water from the driveway sloping to the door | Replace the seal, then check drainage |
| Torn, curled or missing strip | Old rubber or damage from a vehicle | Replace the seal |
| Green or black growth on the rubber | The seal stays wet | Clean it; replace it if stained through |
| Seal is fine but water still comes in | Water is flowing toward the door | Grade, gutters and downspouts; see the OSU Extension checklist |
Close the door, turn out the lights and look for daylight with a flashlight outside.
3Before you replace it
Measure the width of the door and note the seal type. Most seals slide into a retainer or channel. Look at the end of the old seal to see its shape, then take a piece to the store, or send us a photo. Match the new seal to the same channel.
Clopay's guide warns that springs, bottom brackets and cables are under high tension. It says not to loosen or remove the bottom bracket while the spring tension is engaged. A seal change does not need either. If your seal is held by the bracket or you cannot slide it free, stop and call a technician.
4How to replace it
Close the door and disconnect the opener
Pull the red release handle only with the door closed so it cannot move. Unplug the opener if you can reach the plug.
Slide out the old seal
Work from one end and pull it along the channel. If it sticks, trim the end and pull again. Do not pry the aluminum retainer.
Clean the channel
Wipe out dirt and gravel with a rag. Grit stops a new seal from sliding in.
Slide in the new seal
Feed it into the channel from one end and push it through, then trim any extra at the other end.
Check the fit
Look along the bottom for light. Run the door up and down by hand a few times.
Reconnect and test the opener
Re-engage the release handle, then run the door. The door should stop and reverse when it meets an obstruction. If it does not, stop and call for service.
5Water that comes from outside the seal
A new seal will not fix a driveway that slopes to the door. The OSU Extension checklist tells owners to make sure grading and downspouts direct water away from the building and to keep gutters clear. Clear leaves and grit from the door sill, and keep the downspout from emptying near the opening.
Rain may also come in at the sides and top. Clopay lists the perimeter seal in the same checklist, so look there too. See rain and moisture for a full walk-around.
6When to call a technician
Call if the seal will not slide out, the door is crooked, the bottom panel is dented or rusted, or the door is hard to lift. Those can point to a spring, roller or track problem. See garage door repair and new garage doors. Emil Garage Doors repairs and installs garage doors in Oregon, including Hillsboro, Portland and Gresham. Call or send your details with a photo of the bottom edge.
Questions people ask
Can I replace a garage door bottom seal myself?
Often yes, if the seal slides into a channel and you leave the springs, cables and brackets alone. If it will not slide free or the door acts up, call a technician.
Why does water come under my garage door when it rains?
A worn seal, an uneven slab or water running down the driveway toward the door. Check the seal for daylight, then check grading and gutters.
How do I know which seal to buy?
Look at the shape of the end of the old seal and the channel it sits in. A photo to us or a store clerk helps match it.
Does a new bottom seal help with drafts and pests?
It closes the gap along the slab, so it reduces drafts, leaves and pests that squeeze under. Clopay recommends checking it as part of regular inspection.
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