Why Is There a Gap Under My Garage Door in Las Vegas? 7 Causes and How It’s Fixed

Read the Shape of the Gap First

Before anyone buys a seal or touches the opener, it’s worth spending two minutes looking at the gap itself. Different causes leave different patterns, and the pattern narrows things down quickly.

The question that matters most is whether the gap is new and sudden or has been growing slowly. Slow growth over months usually means wear: the seal, the opener setting drifting, the floor settling. A gap that appeared overnight, or right after a loud noise, a stuck door, or a car bumping the door, usually means something broke or moved. That kind gets checked before the door is used again.

Is a Gap Under the Garage Door Dangerous?

A gap from a worn seal isn’t dangerous in itself. It’s a nuisance: dust, heat, water, and pests get in. A gap that comes from the door hanging crooked is a different matter.

A residential sectional door is heavy, and its weight is carried by springs through two lift cables, one on each side. When both cables carry their share, the door stays level. When one cable slips off its drum, stretches, or starts to fray, or when one spring breaks or weakens, more weight shifts to one side. The door tilts, and that tilt shows up as a wedge-shaped gap at the floor. If the opener keeps driving a tilted door, the low side can bind in its track, the high side can pull out of its track, rollers can jump out, and in the worst case a cable can snap or the door can drop. That’s the scenario we want people to avoid.

There’s another safety angle. If someone “fixes” a gap by turning up the opener’s force so it pushes the door harder against the floor, the opener may not reverse when it should. The safety reverse protects people, especially children, and pets. The Consumer Product Safety Commission explains why automatic openers must reverse on contact and have external entrapment protection such as photo-eyes. After any change to the opener or the bottom of the door, test the reverse.

Cause 1: A Worn, Shrunken, or Torn Bottom Seal

What it looks like. Small patches of light along the floor, usually worse at the ends and at low spots. The seal feels stiff when you press it, may have surface cracks or a chalky film, and its ends often stop short of the door edges. You may see a fan of dust inside the door after windy days.

Why it happens here. Most bottom seals are vinyl or a rubber blend. Vinyl stays soft because of plasticizers in the material, and heat and UV slowly drive those out. Las Vegas summers, with highs above 100°F and strong sun, speed that up, especially on doors that face west or south. The seal also sits above a concrete driveway that radiates heat. Over a few summers a basic vinyl seal can go from soft to stiff, and a stiff seal can’t conform to the floor. Seals also shrink in length as they age, pulling back from the corners.

How it’s fixed. On most steel doors, the seal slides into an aluminum retainer channel on the bottom of the door. The old seal comes out, the channel is cleaned and checked for bends or corrosion, and a new seal of the right profile and width goes in, left slightly long and secured at the ends so it can’t creep back. Wood doors usually take a nail-on or screw-on seal. After the new seal is on, the opener’s close limit often needs a small adjustment, because the fuller seal touches the floor sooner, and the safety reverse has to be tested.

What to watch for. The wrong seal profile is the most common DIY mistake. Slide-in seals must match the retainer channel exactly. A bent or corroded retainer won’t hold a new seal straight. And never loosen the bottom brackets at the corners to get the retainer off, because the lift cables attach there under spring tension.

We cover seal replacement in depth in Garage Door Bottom Seal Replacement in Las Vegas: When Should You Replace the Weatherstrip?, and for Summerlin homes in Garage Door Bottom Seal Replacement in Summerlin.

Cause 2: The Opener Stops the Door Short

What it looks like. A uniform line of light the full width of the door, often a half inch or so. The seal is fine. If you watch the door close, it stops and sits just above the concrete. Sometimes the door touches down and then reverses back up instead.

Why it happens. Every automatic opener has travel limits that tell it where “closed” and “open” are. On older openers they’re set with screws or dials on the motor head. On newer ones they’re set electronically with buttons. Limits can be set wrong at installation, drift over time, or be changed by someone trying to stop the door reversing. A common sequence: a new, fuller seal is installed, the door starts reversing at the floor, someone raises the close limit to stop it, and now the door stops short. Heat can play a part too. Some older openers’ limit settings and the door’s own dimensions change a little between hot afternoons and cool mornings.

How it’s fixed. The close limit is set so the door comes fully down and compresses the seal slightly. The force setting is checked and left where the manufacturer intends. Then the door is tested: it must reverse when it closes on a 2×4 laid flat in its path, and it must stop and reverse when the photo-eye beam is broken. If the opener can’t be set to close fully and still pass those tests, it needs repair. Openers that are very old or lack photo-eyes are usually better replaced.

What not to do. Don’t turn up the force to make the door close. That’s the setting that decides how hard the door pushes before it gives up and reverses. Higher force can mean the door won’t reverse on a person or pet. The UL 325 standard exists for exactly this reason.

If your door touches down and goes back up, our guide to a garage door that closes then opens again in Las Vegas covers the other causes, including dirty or misaligned photo-eyes. For opener service see Las Vegas garage door opener repair.

Cause 3: An Uneven, Sloped, or Settled Floor

What it looks like. A gap in one place that doesn’t move: in the middle, at one end, or across a crack in the slab. The door itself looks level against the bricks or siding on either side of the opening. If you put a level on the floor across the opening, you’ll see the dip or slope.

Why it happens. Garage slabs are poured to slope toward the driveway so water drains out, and they’re rarely perfectly flat side to side. Some develop a dip where the driveway apron meets the garage slab. On older homes, slabs can settle unevenly over decades, particularly where soil was disturbed or where water has pooled. Parts of the valley have expansive or collapsible soils that move when they get wet, and long-term irrigation near the driveway can contribute. A crack across the threshold can leave one side slightly lower than the other.

How it’s fixed. For a small dip, the usual fix is a bottom seal with a little more reach, so it fills the low spot while still compressing evenly elsewhere, with the opener’s limit set to match. For a dip or slope that’s too big for a seal, a threshold seal glued to the floor can raise the landing surface where it’s needed. Where the slab has settled badly, or the driveway slopes toward the garage so storm water runs at the door, the right fix may be concrete repair or a drain. That’s work for a concrete contractor, not a garage door company, but it’s important to know before spending money on seals.

What not to do. Don’t try to bend the door or the bottom section to match the floor, and don’t adjust the cables to make one side hang lower. A door has to hang level and balanced to run safely. Make the seal or threshold match the floor, not the door.

Cause 4: A Slipped, Stretched, or Frayed Lift Cable

What it looks like. One side of the door touches the floor and the other doesn’t, leaving a gap that widens toward one end. The door may look tilted in the opening. You might see a cable that’s slack, loose on its drum at the top, or frayed near the bottom bracket. The door may also make new noises or move unevenly.

Why it happens. On a torsion spring door, a steel cable runs from each bottom corner up to a drum on the spring shaft above the door. The springs turn the shaft, the drums wind the cables, and the door lifts evenly. If one cable slips a groove on its drum, it becomes effectively longer or shorter than the other, and the door tilts. Cables can also stretch slightly over years, or fray, often near the bottom where moisture and corrosion attack them. Sprinklers that hit the door and storm water at the threshold speed up corrosion at the bottom brackets. A door that hits an obstruction while closing, or a car that bumps the door, can also knock a cable off its drum.

How it’s fixed. A technician secures the door, relieves spring tension as needed, re-seats or replaces the cable, checks both drums and the bottom brackets, and rebalances the door so both cables share the load. Frayed cables are replaced, usually in pairs. Then the door is tested for balance, the opener limits are checked, and the safety reverse is tested. Cable repair falls under our standard repair range of $150 to $350.

Why it’s urgent. A door hanging on one cable can bind, twist in its tracks, or come off them. A frayed cable can snap. Please don’t try to re-wrap a cable or loosen a bottom bracket yourself. Read more in frayed garage door cable in Las Vegas: can you keep using the door? and garage door cable came off the drum, or see our Las Vegas garage door cable repair service.

Cause 5: A Broken or Weak Spring and an Unbalanced Door

What it looks like. The door may close crooked, slam down faster than usual, or stop and reverse because the opener senses the extra weight. You may see a gap of an inch or two in one of the springs on the shaft above the door. Sometimes the door won’t open at all, or opens a few inches and stops. If one side of a two-spring door is weaker, the gap at the floor can be wedge-shaped, much like a cable problem.

Why it happens. Springs are rated for a number of open-and-close cycles, and every cycle uses some of that life. A busy household can work through a standard spring’s rated life within several years. Springs also lose tension gradually as they age, so the door becomes heavier for the opener to lift and less able to close evenly. Corrosion and lack of lubrication shorten their life. When one spring of a pair breaks, the other is usually close behind, which is why we generally replace them as a pair.

How it’s fixed. The broken or tired springs are replaced with springs sized to the door’s actual weight, wound to the correct tension, and the door is balanced so it stays put when lifted halfway by hand with the opener disengaged. Cables and drums are checked at the same time, since spring failures often stress them. Then the opener’s limits and the safety reverse are tested.

Why not to use the door. With a broken spring, the opener is trying to lift most of the door’s weight on its own. That strains the opener and can bend the door or pull it out of its tracks. Lifting it by hand can also be dangerous, because the door is much heavier than it seems. Our guides loud bang and the door won’t open and can you open a garage door with a broken spring? explain what to do. See Las Vegas garage door spring replacement for service details.

Cause 6: Tracks or Track Brackets Out of Line

What it looks like. The door slows, jerks, or rubs at the same spot every time it closes. One side may land later than the other. You may hear scraping or see rollers that sit at odd angles. Track brackets on the wall may have loose bolts, or the track may be visibly kinked where something hit it. In more serious cases a roller pops out of the track, and the door hangs crooked or stops partway.

Why it happens. Track brackets are lag-bolted to the framing beside the opening, and constant vibration can loosen them over years. Cars, bikes, and stored items bump the tracks. Rollers that are worn or seized drag in the track instead of rolling. A door hanging crooked from a cable or spring problem also pulls on the tracks. Once the track is out of line, the door can bind before it reaches the floor, the opener may stop or reverse because it senses resistance, and a gap appears.

How it’s fixed. A technician checks the tracks for plumb and spacing, tightens or resets the brackets, straightens minor bends or replaces a damaged track section, and replaces worn rollers if needed. If the door is off track, it’s secured and carefully reset, with the cause found and fixed so it doesn’t happen again. Then balance, limits, and the safety reverse are checked.

Don’t force it. If a door is binding or a roller is out of the track, running the opener again can make it worse. Read garage door off track in Las Vegas and why a garage door lifts unevenly or grinds, or see Las Vegas garage door track adjustment.

Cause 7: A Bent Bottom Section or Seal Retainer

What it looks like. A gap near one spot, often near a corner, with a visible bend, kink, or bulge in the bottom of the door. The seal may be popping out of the retainer at that spot. The bottom section may be dented or bowed, or its steel skin may be rusting at the corners where water sits.

Why it happens. Cars backing out too early, the door closing on a trash bin or bike, and storm water or sprinkler overspray at the threshold all hit the bottom of the door hardest. Aluminum retainers bend easily and corrode where water and pool chemicals sit. The steel skin of the bottom section can rust from the bottom up on older doors that sprinklers have soaked for years.

How it’s fixed. A slightly bent retainer can sometimes be straightened. A kinked, split, or corroded one is replaced, then a new seal is fitted. If the bottom section itself is bent or rusted through, a replacement section may be available, or the section can be repaired if the damage is limited. The bottom brackets sit at the ends of the bottom section and hold the lift cables, so any work that touches them must be done with spring tension controlled. That’s not a DIY job. See garage door panel replacement and bent garage door panel repair.

Gaps That Come and Go, and Gaps at the Sides

Not every gap is there all the time. Some appear only on certain days, and some aren’t at the bottom at all. These patterns have their own explanations.

A gap that shows up on cold mornings

Seals stiffen in the cold. A seal that summer heat has already hardened may lose contact on a chilly winter morning, then soften enough to seal again by afternoon. If the opener’s close limit is set so the door only just reaches the floor, the problem is worse. The fix is usually a new seal, a small limit adjustment, or both.

A gap that shows up on hot afternoons

Steel doors and aluminum retainers expand a little in the heat, and a long double door can bow very slightly when the sun hits its face. On most doors this is minor. If a door’s reinforcing strut is missing or bent, or the door is already slightly bowed, the heat can be enough to lift the middle off the floor. A strut repair or the right seal usually handles it.

A gap that appeared after a storm

Monsoon gusts can push on a closed door hard, and storm water at the threshold can wash grit under the seal or soften the soil under a slab edge. If a gap appeared after a storm, check for debris under the seal first, then look at whether the door is still level.

A gap that appeared after the car touched the door

Even a light bump can bend the retainer, kink a track, or knock a cable off its drum. If the door was hit, have it checked before running it again, especially if it now looks crooked.

Gaps at the sides or top

Light at the sides or top of the door usually isn’t the bottom seal. It’s the perimeter weatherstrip, the vinyl stop molding on the jambs and header with a flap that rests against the door. In the Las Vegas sun those flaps crack and curl, and dust comes in at the sides. Replacing the stop molding fixes it. It should touch the door lightly; molding set too tight drags on the door and makes the opener work harder. A gap at one side that’s much wider than the other can also mean the door has shifted in its tracks, which takes us back to cause 6.

Which Causes Show Up on Which Las Vegas Homes

Across the valley, the age and setting of a home shift the odds between the seven causes. This isn’t a rule, but it’s a useful starting point.

• Older central and east-side homes. Settled slabs and threshold dips (cause 3) are more common, along with retainers that have been bent or corroded over decades (cause 7). Doors have often been replaced at least once, so parts can be mixed.
• 1990s and 2000s tract homes in the northwest, southwest, and Henderson. Worn builder-grade seals (cause 1) and springs reaching the end of their cycles (cause 5) are the usual suspects. Many of these doors are on their second or third set of springs.
• Newer homes. Slabs are usually flatter and seals newer, so an even gap often points to an opener close limit that was set short at installation (cause 2). Construction dust from nearby building sites can also wear seals early.
• Homes with sprinklers aimed at the driveway. Corroded bottom brackets and frayed cable ends (cause 4) and rusted bottom sections (cause 7) show up more often where water hits the door every day.
• Rentals. Tenants often don’t report a gap until dust or pests get bad, and a crooked door can go unnoticed. Check the bottom of the door at every turnover.
• Busy households with several drivers. High daily cycles wear springs and rollers faster (causes 5 and 6), and more cars mean more chances to bump a track or the bottom of the door.

Whatever kind of home you have, the fastest way to the right fix is the same: read the shape of the gap, check that the door hangs level, and test the safety reverse. Then fix the cause, not just the symptom.

What Each Fix Costs in Las Vegas

Two points worth knowing. First, more than one cause is common. A door with a frayed cable often has a tired seal too, and the opener limit may have been changed to compensate. A good technician will show you each problem and price each fix, so you can decide. Second, fixing the cause first usually saves money. Putting a thicker seal on a crooked door costs money now and doesn’t prevent the cable or spring failure that’s coming. See our Las Vegas garage door repair cost guide for how we price work.

Why a Gap Under the Door Is a Bigger Deal in Las Vegas

In a mild climate, a small gap under the garage door is mostly a draft. In Las Vegas it’s an open invitation for four things.

This is why we suggest checking the bottom of the door before summer and again before monsoon season. Our pre-summer maintenance checklist includes the seal along with springs, cables, rollers, and photo-eyes, and a garage door tune-up, posted at $89 to $129, includes a weather-seal check.

Safe Checks You Can Do Yourself

You can narrow down the cause without touching any part under tension. Keep hands away from springs, cables, drums, bottom brackets, and the joints between sections.

1. Look at the gap. Close the door, turn off the garage lights on a sunny day, and note where light shows and whether it’s patches, an even line, a middle dip, or a wedge.
2. Look at the door in the opening. From outside, compare the bottom of the door to the brick or stucco lines on each side. Is it level, or tilted?
3. Look at the seal. With the door closed, press it with a thumb. Soft and springy, or hard and cracked? Do the ends reach the door edges?
4. Look at the cables and springs from a distance. Do both cables look tight and similar? Is there a visible gap in a spring on the shaft above the door? Don’t touch them.
5. Watch a full close. Does the door travel smoothly, land on both sides at once, and stop on the floor? Or does it stop short, reverse, or land one side first?
6. Test the safety reverse. Lay a 2×4 flat on the floor under the door and close it. The door should reverse after touching the board. Then break the photo-eye beam with a box while it’s closing; it should stop and reverse. If either test fails, stop using the opener.

If what you see is patches of light and a hard seal, cause 1 is the likely answer. An even line and a good seal points to cause 2. Anything with a tilt, a slack cable, a gapped spring, or a sudden change should be checked by a technician before the door is used again.

How a Technician Diagnoses a Gap Under the Door

When we come out for a gap, here’s the order we work in. It’s designed to find the real cause, not just the obvious one.

• Watch the door run. Open and close with the opener, listening and watching for binding, uneven travel, and how it lands.
• Disengage the opener and check balance. Lift the door by hand to about halfway. A balanced door stays put. One that drops or rises points to spring problems.
• Inspect cables, drums, and bottom brackets. Look for fraying, slack, a cable off its groove, and corrosion at the brackets.
• Inspect springs. Look for gaps, stretching, and corrosion, and check whether the springs suit the door’s weight.
• Check tracks and rollers. Plumb, spacing, bracket bolts, bends, and roller condition.
• Check the bottom of the door. Seal condition, retainer straightness and corrosion, and the bottom section itself.
• Check the floor. Dips, slope, cracks, and the driveway grade.
• Check the opener. Limits, force, photo-eye alignment, and the safety reverse.
• Explain and price. Show you what was found, explain which fix addresses the gap, and give you prices before any work starts.

If you’d like to verify any contractor before they work on your door, Nevada contractors must be licensed by the Nevada State Contractors Board. You can check a licence on the board’s public licence search. Open Sesame Garage Door Repair Las Vegas holds licence #0083315.

Gap Myths and Bad Fixes

Related Open Sesame Guides

• Garage Door Bottom Seal Replacement in Las Vegas: When Should You Replace the Weatherstrip?
• Garage Door Bottom Seal Replacement in Summerlin: When Should You Replace the Weatherstrip?
• Garage Door Won’t Close in Las Vegas: 10 Causes
• Garage Door Closes Then Opens Again in Las Vegas
• Why Is My Garage Door Lifting Unevenly or Making a Grinding Noise?
• Garage Door Off Track in Las Vegas
• Frayed Garage Door Cable in Las Vegas
• Garage Door Repair Las Vegas, NV: Complete 2026 Guide
• Las Vegas garage door repair
• Las Vegas garage door repair cost guide

About Open Sesame Garage Door Repair Las Vegas

Open Sesame Garage Door Repair Las Vegas repairs residential garage doors across the Las Vegas Valley from 7865 Bluewater Dr, Las Vegas, NV 89128. We hold Nevada contractor licence #0083315 and we’re open 24 hours. This guide is based on the causes of floor gaps our technicians see on Las Vegas doors, the posted prices on our cost guide, and safety guidance from the CPSC, DASMA, and the UL 325 standard.

Call (702) 888-0842, or view Open Sesame Garage Door Repair Las Vegas on Google Maps.

Frequently Asked Questions About a Gap Under a Garage Door in Las Vegas

Find Open Sesame Garage Door Repair Las Vegas

View Open Sesame Garage Door Repair Las Vegas on Google Maps · Serving the Las Vegas Valley from 7865 Bluewater Dr, Las Vegas, NV 89128