A garage door bottom seal is the rubber or vinyl strip held in the aluminum retainer along the bottom edge of a steel door. When it cracks, flattens or tears, rain, dust, leaves and rodents get in under the door. We fit a new seal matched to your retainer, replace a corroded retainer, add side weatherstrip and threshold seals, and reset the opener to close on it.
What you get
- New bottom seal sized to your retainer channel, in the matching T-end or bead profile
- Corroded or bent retainer replaced, common on coastal doors where salt air eats the aluminum
- Vinyl stop molding along the sides and top, so light and wind stop coming in around the edges
- Threshold seal on the slab for dips the bottom seal alone cannot follow
- Opener close limit reset so the door seals without bouncing back up
What wears out along the bottom of the door
On a steel sectional door, the bottom seal slides into a retainer: an aluminum channel fastened across the bottom of the lowest section. Seals come in profiles that match the channel. A T-end seal has T-shaped edges for a retainer with T slots, and a bead seal has round beads for a retainer with round channels. When the door closes, the seal squashes against the slab and fills the gap.
Sun and heat bake the seal until it goes hard, cracks and shrinks back from the ends. Gaps open at the corners first, which is exactly where mice and rats look for a way in.
Older wood doors and one-piece tilt-up doors usually have no retainer. Their seal is nailed or screwed to the bottom rail, and we replace it the same way.
Retainers: when the channel is the problem
A new seal only works if the retainer can hold it. Three things go wrong with the channel:
- Corrosion. Near the beach, salt air and wet sand eat the aluminum until the slots crumble. Doors in Ocean Beach and Pacific Beach lose retainers far sooner than inland doors.
- Bends and kinks. A bumper, a dragged trash can or a door closed on a toolbox bends the channel, and the seal pops out of it.
- Odd sizes. Door makers use different slot shapes and seal widths, so a seal picked off a store shelf often does not fit.
We measure the channel and match the seal to it. If the retainer is too far gone, we fit a new one across the full width of the door before the seal goes in.
Safety: the bottom brackets at each end of the retainer hold the lift cables under full spring tension. Never unbolt them to free the retainer.
Need a new garage door seal today?
Call or text with your address, single or double door, and what the door is doing. The price is firm before the truck leaves the yard.
Sides and top: perimeter weatherstripping
The bottom seal handles the floor. The sides and top of the opening are sealed by stop molding: a strip fastened to the jambs and header with a soft vinyl flap that presses against the face of the closed door.
Old stop molding is often painted wood with no flap left, or vinyl that has gone brittle and curled. You see it as daylight around the edges of the closed door, dust lines along the jambs and leaves blown in after a windy night.
We fit new vinyl stop molding along both jambs and the header, set so the flap touches the door without dragging on it. Set too tight, it rubs and makes the door work harder. Set too loose, it seals nothing.
Uneven slabs, threshold seals and the opener
Garage slabs settle and crack, and many dip toward the driveway. A seal with a taller bulb follows a gentle dip. A deeper low spot leaves a gap no seal on the door will close.
That is where a threshold seal helps: a rubber strip glued to the slab under the closed door, so the bottom seal lands on a raised edge. It also turns back rainwater running down a driveway that slopes toward the garage. We pick a low profile so cars, bikes and trash cans roll over it.
Any new seal changes where the door meets the floor, so we reset the opener's close limit. Skip that step and the opener can read the thicker seal as an obstruction and send the door back up.
Gap at the bottom: a seal problem or a cable problem?
Before replacing a seal, we look at the shape of the gap, because a crooked door is not a seal job.
- Even gap, or gaps only at the corners: a worn seal, a bent retainer or an uneven slab. This page fixes it.
- Gap on one side only, door sitting crooked: usually a frayed or snapped lift cable, or a cable off its drum. That needs cable repair, not a seal.
- Door stops short of the floor all the way across: usually the opener's close limit, or a door that has come off its tracks.
Safety: if the door is crooked, keep people and cars out from under it and do not run the opener. The gap at the bottom page has the full list of safe checks.
Rodents, dust, rain and embers across San Diego County
What gets in under the door depends on where you live.
- Near canyons and open space, rodents looking for shelter find the corner gaps. The gap a mouse can squeeze through is smaller than most people expect.
- In the inland valleys, from Lakeside to Escondido, summer heat bakes seals until they crack, and Santa Ana winds blow dust and dry leaves under them.
- Near open land, the same gaps let wind-blown embers in during fire season. Our fire season guide covers the ember gap and how to close it.
- Anywhere, winter rain running down a driveway that slopes toward the garage finds the low corner of the slab.
If the door is due for a look anyway, a tune-up on the same visit checks the rest of it.
Bottom Seal and Weatherstripping: common questions
How do I know if my garage door bottom seal needs replacing?
Look at the bottom of the closed door from inside with the lights off. Daylight under the door, water or leaves on the slab after a storm, dust lines along the floor or droppings near the corners all point at a worn seal. Up close, a bad seal is hard, cracked, flattened or pulling out of its retainer at the ends.
Will any garage door bottom seal fit my door?
No. Steel doors hold the seal in a retainer channel, and the seal has to match it: a T-end seal for a retainer with T slots, a bead seal for one with round channels, in the right width. Wood and older one-piece doors use a seal fastened straight to the bottom rail. We measure the retainer and bring the matching seal, or replace a corroded or bent retainer.
What if my garage floor dips under the door?
A seal with a taller bulb follows a gentle dip in the slab. A deeper low spot needs a threshold seal glued to the floor so the door lands on a raised edge, which also turns back water running down the driveway. Large cracks and heaved slabs are concrete work, not garage door work.
Why does my garage door go back up after a new bottom seal?
A thicker seal touches the floor sooner, and the opener can read that as an obstruction and reverse. The fix is resetting the opener's close limit so it stops on the new seal, then running the safety reverse test. If the door reverses before it reaches the floor, the safety sensors or the tracks are the more likely cause.
Do you replace the weatherstripping on the sides and top of the door?
Yes. The sides and top are sealed by stop molding, a strip on the jambs and header with a soft vinyl flap that presses against the closed door. When it has cracked, curled or lost its flap, we fit new vinyl stop molding along both jambs and the header, set so it touches the door without dragging. It is often done on the same visit as a bottom seal.
The FAQ page has more answers. Not sure which part failed? Send a photo and we will name it.
Where we do this
We cover all of San Diego County, same day in most cases. Some of the places we work:
Related guides
- Garage Door Maintenance Near the Coast: A San Diego Guide: What salt air does to garage door springs, cables, tracks and brackets near the San Diego coast, what you can safely maintain, and a seasonal checklist.
- Repair or Replace Your Garage Door? How to Decide: When a sectional garage door is worth repairing and when it needs replacing: springs, cables, dented sections, rot, rust and typical San Diego costs.
- Garage Door Fire Season Prep: A San Diego Checklist: Before Santa Ana season: seal the ember gap under the garage door, test the opener's backup battery, learn the manual release and photograph it all.
Ready to get the door moving again?
One call or text gets you a straight answer and a firm price before the truck rolls. Mon to Sat 7am to 7pm.