A gap or daylight under a closed garage door usually comes from a worn or flattened bottom seal. Read the gap. Safety: a door lower on one side may have a failing cable, so stop using it. Even gap: a worn seal or a short travel limit. One end: a sloping slab or a crooked door. Middle: a dip in the slab or a bent bottom section.
Likely causes
- A bottom seal that is torn, flattened, brittle or missing
- A slab that has settled, cracked or slopes across the opening
- An opener travel limit set so the door stops short of the floor
- A bottom section bent by a bumper, or a door hanging crooked on a worn cable
- Worn weatherstrip at the sides and top letting light in around the edges
What you are seeing
With the garage lights off, there is a line of daylight under the door, or a wedge of light at one corner. Leaves, dust and sand pile up inside the door after a windy day. Rain runs in under the door during a storm and pools on the floor.
Maybe you are finding mouse droppings, roaches or crickets where nothing used to get in. Or the door simply does not look like it meets the ground when it is closed.
The shape of the gap says a lot about its cause, so look at it closely before anything else. Even all the way across, wider at one end, or open in the middle each point somewhere different.
What usually causes it
- Even gap all the way across: a worn bottom seal, or a door that stops short because the opener's travel limit is set too high. Seals flatten, crack and shrink with sun and age.
- Gap at one end only: a slab that slopes or has settled, or a door hanging crooked. A crooked door can mean a lift cable is frayed or slipping on its drum; see cable snapped or off the drum.
- Gap in the middle: a dip in the slab, or a bottom section bowed upward where a bumper hit it.
- Light at the sides and top: worn perimeter weatherstrip along the jambs and header, not the bottom seal.
Pests, rain and wind-blown embers all use the same gap. Homes in designated wildfire areas have a code limit on it, which our fire season guide explains.
Need a new bottom 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.
What you can safely check in two minutes
Never loosen or pry at the bottom brackets. They sit at the corners where the seal ends and hold spring tension.
- Read the gap. With the lights off, note where daylight shows: across, at one end, or in the middle.
- Look at the seal for tears, flat spots and missing lengths.
- Look at the cables and springs. A slack or frayed cable on the low side means call, not adjust.
- Watch it close. A door that stops an inch above the floor every time usually has its travel limit set short.
Which repair fixes it
- A worn, torn or flattened seal: a new seal in the right profile for your retainer, and a new retainer if it is bent or corroded, through our bottom seal and weatherstripping service.
- An uneven slab: a taller seal that can fill a larger gap, plus a threshold seal on the floor where it helps.
- A door that stops short: the close limit reset and the force and reverse tested, through opener repair.
- A crooked door: cable and drum replacement.
- A bent bottom section: measured and quoted on panel replacement.
When a repair stops making sense
A seal is a small part, so the real question is usually about the door.
- A bent bottom section. A new seal cannot close a gap left by a bowed section. Sections are ordered to match the door's make, model, color and panel design, which is straightforward for many Clopay and Amarr doors; on a discontinued model, a matching section may not exist.
- A rotted wood bottom. On older wood doors and one-piece tilt-ups, water wicks into the bottom rail. Once it is soft, a seal has nothing to hold.
- A badly broken slab. That is concrete work, and no seal can bridge it.
When a new door is the better answer, that is a job for a licensed contractor, and we will say so.
Across San Diego
In Spring Valley, many homes sit on sloped lots around Dictionary Hill and Casa de Oro, and where a slab has settled, the closed door leaves a wedge of daylight at one corner. A taller seal often closes it.
In Lakeside, summer heat and Santa Ana winds bake bottom seals until they crack, and the same winds push dust, leaves and, in fire season, embers at any gap.
Down in Ocean Beach, onshore wind pushes sand and damp air under a worn seal. A seal that meets the floor pays off in all three places.
Gap at the Bottom or Daylight Showing: common questions
Why is there a gap under my garage door?
Most often the bottom seal has worn, flattened or torn. Other causes are a slab that has settled or slopes, an opener set to stop short of the floor, a bent bottom section, or a door hanging crooked from a cable problem. The shape of the gap tells you which: even all the way across, wider at one end, or open in the middle.
Should I see any daylight under my closed garage door?
No. With the door closed, the bottom seal should press against the floor along its whole length, with no daylight showing. A visible line of light, a gap you could slide a finger into, or water coming in during rain means the seal, the opener settings or the door itself needs attention.
Can wildfire embers get in through the gap under my garage door?
Yes. Wind carries embers well ahead of a fire, and a gap under or around the garage door is one of the openings they use. Inside, they land on boxes, rags and the car. A bottom seal that meets the floor along its whole length, with weatherstrip at the sides and top, closes that path. Homes in designated wildfire areas also have a code limit on those gaps.
Why does my garage door stop before it touches the ground?
Usually the opener's close travel limit is set too short, sometimes on purpose after the door kept reversing. It can also be something the door binds on near the bottom of the track. We reset the limit so the seal meets the floor, then test the force and auto-reverse so the door still stops and reverses on an obstruction.
Will a new garage door seal keep mice and rain out?
A bottom seal that meets the floor along its whole length is the main barrier against rain, blown leaves and pests coming in under the door. Gaps at the sides and top need the perimeter weatherstrip too. Pests also get in through vents and wall gaps, so a seal helps a lot but is not a complete pest fix.
The FAQ page has more answers. Not sure which part failed? Send a photo and we will name it.
Where we see this
We cover all of San Diego County, same day in most cases. Some of the places we work:
Related guides
- 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.
- 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.
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