Garage Door Bottom Seal Cracked and Hardened
Most of what's written about bottom seals describes a strip of rubber that tears, splits, or gets chewed up. That is a real failure and we do see it. It is not, however, the one that brings people to this page in Mesa or Gilbert.
Here the seal usually dies with its dignity intact. Years of afternoon sun through the gap and 115-degree concrete underneath drive the plasticizers out of the rubber, and it goes stiff. It still spans the bottom edge. It still looks like a seal. It has simply stopped being springy enough to squash against the floor, so a line of daylight appears under a door that is closing perfectly.
That's why people replace a seal, see no change, and conclude something bigger is wrong. They were reading the wrong symptom. The question isn't whether the rubber is torn — it's whether it still compresses.
This is general guidance based on what we see on service calls — it isn’t a substitute for someone looking at your actual door. Every door is a little different, and if anything here feels beyond what you want to take on, stop and give us a call.
What to check in the next 10 minutes
Four checks, all from outside, none needing anything but a thumb and a flashlight. They separate a spent seal from a floor problem in about three minutes.
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1Press the rubber with your thumb
Door closed. Crouch at the bottom edge and push the exposed rubber in hard, then let go. A seal with life in it dents under your thumb and springs straight back. A spent one barely moves, or it moves and stays dented — it behaves like a piece of plastic trim rather than rubber. This single test decides most of the page.
You’ll know it worked when: You can say whether the rubber rebounds or stays where you pushed it.
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2Read the daylight from inside, lights off
Shut the garage door, kill the lights, and let your eyes adjust for a minute. An even hairline of light across the whole width means the rubber has stopped compressing. Light at one spot, in a shape that follows the concrete, means the floor. Light at one end that widens toward the corner means the door isn't hanging level.
You’ll know it worked when: You can describe the shape of the light, not just that it's there.
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3Check both ends of the seal
Look at where the rubber stops at each corner of the door. A hardened seal shrinks lengthwise as well, and the classic result is a couple of inches of empty retainer channel at one or both ends. People miss this because they're looking at the middle of the door, which is the part that still looks fine.
You’ll know it worked when: You've looked at both corners and know whether the rubber runs the full width.
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4Feel the outside face for crazing
Run a finger along the weather side of the seal. Hardened rubber develops a fine web of surface cracks — like dried mud on a small scale — long before it splits through. That crazing is confirmation of the same failure the thumb test found, and it shows up first on the sunniest part of the door.
You’ll know it worked when: You know whether the outer face is smooth or has started to check and craze.
First question: does the rubber still spring back?
Everything downstream depends on this. It takes five seconds and it sends you to two completely different places.
If the daylight is at one end only and gets wider toward that corner, put the seal down and go look at how the door is hanging. That's a level problem, and a new seal will not close it.
Which version are you looking at?
Six patterns cover nearly everything we're called out to. Find yours, then jump to the cause.
Classic hardened astragal. The rubber is uniformly stiff, so it fails uniformly.
Jump to that fix ↓Surface crazing from UV. The same failure, caught earlier.
Jump to that fix ↓The rubber shrank or slid, leaving bare retainer at the corner.
Jump to that fix ↓The aluminum channel is the problem, not what's in it.
Jump to that fix ↓The concrete, not the rubber. A different fix and a different page.
Jump to that fix ↓The door isn't finishing its travel. That's the opener or the counterbalance.
Jump to that fix ↓What's actually along the bottom of your door
There are two parts down there and mixing them up is why replacement advice online is so confusing. The rubber strip itself is the astragal. It sits in a retainer — an aluminum channel screwed or riveted along the bottom edge of the bottom section, with one or two slots running its full length. The astragal has beaded edges that slide into those slots from one end, like a key into a lock, and that's the only thing holding it on.
The rubber is not there to plug the gap by being thick. It's there to be squashed. A healthy astragal deforms when the door's weight settles onto it, spreading out against the concrete and following whatever the floor is doing at that point. That deformation is worth perhaps half an inch of tolerance, and it's the entire reason a garage door can seal against a slab that isn't flat.
So the property that matters is flexibility, not thickness or condition. When rubber loses flexibility it stops deforming, and a strip that won't deform is a strip that only touches the floor at the high spots. You get a door that closes exactly as it always did, sitting on a seal that looks exactly as it always did, with light underneath it.
Worth knowing before you go further: the retainer is attached to the bottom section, which also carries the bottom brackets at each corner. Those brackets are under the full pull of the lift cables and they wear factory warning labels for that reason. Changing an astragal never involves touching them — the rubber slides out the end of the channel, and nothing about that job goes near a bracket bolt. If a set of instructions has you loosening one, you're reading instructions for a different job.
One sentence version: you're not judging whether the rubber looks damaged, you're judging whether it still squashes. And the pass mark isn't a matter of taste — DASMA's own home-inspection checklist, TDS #167, asks a yes-or-no question about this: “Does the door fully close and rest on the floor with no gap?” That's the standard the industry publishes, and a strip of daylight is a No.
Reading the gap
Match what you're seeing along the bottom edge. The right-hand column is our honest read on who this belongs to.
| What you’re seeing | Most likely cause | How urgent | Who should fix it |
|---|---|---|---|
| Even thin line of light, seal stiff to the thumb | Astragal hardened by heat and UV — the standard failure here | Fix this month | You can do this |
| Fine cracks across the outer face, still sealing | Early UV crazing — the seal is on its way out | Plan for it | You can do this |
| Rubber missing at one or both ends | Shrinkage or the astragal working out of the channel | Fix this month | You can do this |
| Seal split lengthwise or hanging in a flap | Something was closed on it, or the rubber finally gave after hardening | Fix this week | You can do this |
| Channel kinked, crushed, or pulled away from the section | Retainer damage — usually from an impact | Fix this week | Either — call us if unsure |
| Seal soft, gap only in one dished area of the floor | The slab, not the door | Fix this month | Either — call us if unsure |
| Gap widens steadily toward one corner | The door is hanging out of level — cables or drums | Stop using it | Call a pro |
| New seal fitted, opener now strains or bounces at the floor | The door closes higher on fresh rubber than it did on flat rubber | Fix this week | You can do this |
| Seal sticks to the concrete and peels loose as the door opens | Softened rubber gripping hot slab — a heat effect, not damage | Monitor | You can do this |
| Gap appeared over a few weeks with no seal change | Something moved — the door, the springs, or the concrete | Fix this month | Either — call us if unsure |
What’s actually causing it
These are ordered the way we work through them on a real service call — cheapest and most common first, so you don’t start by replacing a part that was never the problem.
Heat and UV have hardened the rubber
Basic checkThe dominant failure in this valley and the one nobody writes about. Rubber compounds rely on plasticizers to stay flexible. Sustained heat drives them off, and ultraviolet light attacks the polymer chains at the surface. Do both for a few years and you get a strip that has kept its shape while losing the one property it was fitted for.
The numbers are unkind here. A bottom seal in a temperate climate is often good for eight to ten years. On a south- or west-facing door around Mesa, Chandler or Queen Creek, we replace them at two to four. The door spends the hottest hours of the day facing directly into the sun with the concrete under it radiating back, and the seal takes both sides of that.
Because the strip stays whole, the usual advice — look for tears — returns a clean bill of health on a seal that stopped working a year ago.
How you can tell: The thumb test. It stays dented, feels like hard plastic, and makes a dull knock rather than a soft thud if you tap it. The daylight underneath is even across the door.
- Do the thumb press at three points: both ends and the middle. Hardening is usually worst wherever the sun sits longest.
- Compare against a piece of rubber you know is healthy — the seal on a side service door, or a new piece if you have one.
- Check the outer face for crazing while you're down there. Fine surface cracking confirms it.
- Note which way the door faces. South and west exposures fail fastest and are worth checking a year earlier than the rest.
- Measure the door's width and look at the end profile of your existing astragal before buying anything — the beaded shape has to match the retainer's slots.
- Replacement is a straightforward job on a closed door and it's covered step by step on our weather stripping page.
You’ll know it’s right when: New rubber dents and rebounds under a thumb, and with the door closed and the lights off there's no line of daylight along the bottom.
The rubber has crazed and split through
Basic checkThe visible end of the same process. Hardened rubber can't flex, so every cycle of the door works it in a way it can no longer absorb, and it starts to fracture — usually along the fold line where a bulb seal collapses, or across the face where the strip bends around the retainer's lip.
Splitting is also what happens when a hardened seal meets an object. A soft astragal closed onto a hose or an extension cord deforms around it and shrugs it off. A brittle one tears. That's why people connect the failure to the day they closed the door on something, when in fact the rubber had already lost the ability to survive it.
Once it's split through, the gap is no longer a hairline. It's an open channel with a flap of rubber next to it, and everything that gets in through a gap starts getting in.
How you can tell: Visible cracks you can get a fingernail into, a section hanging loose, or a chunk missing. Often worse at one end than the middle.
- Look along the full width from outside with a flashlight held low, so the light rakes across the rubber rather than shining at it.
- Check the fold on a bulb seal — that's where a hardened one splits first, and it's hidden until the door is up.
- Check whether the split runs through to the daylight side or is only surface crazing. Through-splits let water and grit in immediately.
- Look for what caused it if the tear is localized — a nail head standing proud of the slab, a piece of rebar tie, a screw in the concrete.
- If something on the floor did it, deal with that first or the new seal goes the same way.
- Replace the full length rather than patching. Astragal is sold by the foot and a spliced seal leaks at the splice.
You’ll know it’s right when: The full width is one continuous, unbroken strip with no flaps, and nothing on the slab is sharp enough to start the next tear.
The astragal has slid out of the retainer at one end
Basic checkVery common and very easy to miss, because the failure is at the corner and everyone inspects the middle.
The rubber is held only by its beaded edges sitting in the channel's slots. Nothing pins it. Two things dislodge it: hardened rubber shrinks lengthwise over time and pulls its own ends inward, and a door that drags its seal on hot concrete gets a small tug on every close. Give either one a few years and you have bare aluminum channel at one end of the door.
That bare end matters out of proportion to its size. It sits at the exact corner where the bottom seal is supposed to meet the vertical seal down the jamb, and a couple of inches of missing rubber there is a straight, open path from the driveway into the garage.
How you can tell: Empty channel visible at one or both corners, or a seal that clearly doesn't run the full width of the door.
- Look at both bottom corners with the door closed, from outside, at eye level with the slab.
- If the rubber has only crept a little and is still flexible, you can sometimes work it back along the channel by hand from the end.
- Check whether the end of the channel is open or has a stop. Some retainers take a small plug or a screw at the end to keep the seal from walking.
- Look at what the missing rubber has exposed — the corner is the highest-value spot on the whole perimeter for keeping things out.
- If the rubber has shrunk rather than slid, it won't stretch back. That's a replacement.
- Once new rubber is in, look at how it meets the vertical jamb seal at each corner. That junction is its own subject and it's covered on our pest exclusion page.
You’ll know it’s right when: Rubber runs corner to corner with no bare channel showing, and the ends sit flush with the ends of the retainer.
The retainer channel is bent, packed, or corroded
Hands-on — moderate riskOccasionally the aluminum is the problem. A retainer that has been struck — a bumper, a jack handle, a trailer tongue — gets a kink in it, and a kinked slot won't let rubber slide through or hold it square once it's there.
The other version is packing. Fine silt and grit ride in on runoff and get worked into the channel every time the door closes, and after a monsoon season there can be a compacted line of dirt in there. That does two things: it stops a new seal seating fully, and it holds moisture against the aluminum. Aluminum in contact with damp mineral grit corrodes into a chalky white bloom that swells and makes the slot narrower still.
None of it is dramatic. It's just the reason a new seal sometimes won't go in, or goes in and sits proud on one side.
How you can tell: You can see a kink or flat spot in the channel, or the old seal came out and the slot is full of packed dirt. New rubber binds partway along instead of sliding.
- With the old seal out, look down the length of the channel from one end. It should be dead straight.
- Clear the slots with a stiff brush and a vacuum, then a rag. Take your time — this is most of the job on an older door.
- Rinse if it's badly packed, and let it dry fully before fitting new rubber.
- A light spray of silicone lubricant in the channel makes the new astragal slide instead of fighting you. Silicone or white lithium grease — not the classic blue-can penetrant, which thins out and attracts more dust than it repels.
- If there's a kink, stop and assess rather than hammering it flat. A distorted retainer usually needs replacing, and that's a bolt-on part.
- Check the retainer is still tight to the section along its whole length — fasteners work loose and a channel that has come away from the door lets air past behind the seal.
You’ll know it’s right when: The channel is straight, clean and firmly attached, and new rubber slides through it under hand pressure alone.
The seal is fine — the door is closing higher than it used to
Hands-on — moderate riskA soft, intact seal with daylight under it is a message about the door rather than the rubber.
The most common version is straightforward: the opener's down travel limit is set slightly short, so the door stops before the seal has been squashed. This turns up constantly right after somebody fits a new seal — fresh rubber is taller and stiffer, the opener hits its old stopping number early, and the customer concludes the new seal is faulty.
The other version is slower and more worth catching. As springs lose tension the door gets heavier, and a heavier door can settle or stall differently at the bottom of its travel. A door that has gradually stopped seating over a season, with no change to the seal at all, is often reporting on its counterbalance rather than its weatherproofing.
How you can tell: The rubber passes the thumb test and looks new-ish, but the door visibly stops with the seal barely touching the concrete. Often the gap is dead even across the width.
- Watch the last six inches of travel from outside. Does the seal flatten against the concrete, or does the door stop with it just kissing the floor?
- If it stops early, the down travel limit is the place to look — that adjustment lives on the opener and we cover it on the travel limits page.
- If you've just fitted a new seal, expect to reset the limit. It's normal rather than a fault.
- Disconnect the opener with the door closed and lift by hand to check the door's weight and balance before you chase settings any further.
- A door that feels heavy or won't hold position is a counterbalance issue, and no amount of seal or limit work touches it.
- After any travel change, lay a scrap 2x4 flat on the concrete under the center of the door and confirm it reverses on contact.
You’ll know it’s right when: The door drives down until the seal visibly flattens, the opener stops without straining, and contact reversal still works.
The seal is fine and the concrete isn't flat
Hands-on — moderate riskGarage slabs are poured with a slope for drainage, and plenty of them have picked up a dish, a low corner, or a crack with a lip since. A seal can only follow so much. Half an inch of squash is generous; an inch of dip in the slab is beyond it.
The tell is the shape of the light. Seal failure produces an even line, because the rubber is equally stiff everywhere. A floor produces a lens — widest in the middle of the low area, tapering to nothing at each side of it, and always in the same place. Put a straightedge across the opening and the story usually finishes itself.
There's a bigger version of this that's specific to Arizona soil, where one corner of the slab has genuinely dropped and the door has started to rub the jamb as well. That's not a seal question at all and it has its own page.
How you can tell: Light concentrated in one area with a curved shape, in the same place every time, with soft flexible rubber above it.
- Lay a long straightedge or a level across the opening on the concrete and look for daylight under it.
- Check whether the low spot lines up with where the light appears. It usually does, and that ends the investigation.
- A thicker bulb-style astragal takes up more variation than a flat T-style, and that's the first thing to try.
- For a bigger dip, a bonded floor threshold gives the seal something flat and slightly raised to close against. It's fitted to the slab rather than the door.
- If the gap is at a corner and the door has also started catching the jamb when it moves, stop treating it as a seal problem.
- Take a photo of the light pattern with the lights off. It's the single most useful thing you can show us on the phone.
You’ll know it’s right when: You know whether the gap follows the door's bottom edge or the concrete's contour, and you've picked a seal profile that matches which one it is.
What you’ll need if you’re doing this yourself
- Your thumb — the compression test outranks every other diagnostic on this page and costs nothing
- A flashlight held low and raked along the seal — surface crazing is invisible under overhead light and obvious under a raking beam
- A tape measure — door width plus the seal's profile is all the information a supplier needs
- A long straightedge or a four-foot level — settles the seal-versus-floor question in about a minute
- A phone camera — a photo of the light pattern with the garage lights off tells us more than any description
Things not to do — and why
The failure here is loss of flexibility, and a hardened seal looks perfect right up until you press it. Nearly every 'my new seal didn't help' call traces back to reading condition instead of testing compression.
The bottom edge has to move a few hundred times a year. Anything that bonds the door to the slab either tears free within a week or holds the door down long enough for the opener to fight it.
Close force is half the contact-reversal system. Setting the opener to crush a seal sets it to push through anything else it meets at the same height.
The bottom brackets there carry the full pull of the lift cables and are labeled from the factory for that reason. No part of an astragal job requires touching them — the rubber slides out of the end of the channel.
The splice is a permanent hole at exactly the height everything wants to come in at. Buy the full width.
It's soft aluminum with a slot that has to stay square. A gouged or spread slot won't hold new rubber flat, and you'll be replacing the channel instead of the seal.
Thicker rubber changes where the door effectively closes, so the opener's down limit often needs resetting afterwards. If you skip that, the door either strains at the bottom or bounces back off the floor.
Why seals die young here
This is one of the few garage door parts where the Arizona difference isn't a nuance — it's the whole story. The national rule of thumb for a bottom seal is eight to ten years. We replace them at two to four across Mesa, Gilbert and Queen Creek, and the ones facing west are on the short end of that.
The mechanism is heat plus ultraviolet, working from both directions. Direct sun on the outer face for the hottest six hours of the day, and slab temperatures underneath that stay high long after the sun has moved. Rubber that is cycled through that every day for a few summers loses the plasticizers that made it flexible, and once flexibility is gone the seal has nothing left to offer.
- Two to four years, not eight to ten — the national figure assumes a climate that lets rubber stay rubber. Plan on checking yours annually rather than when it looks bad.
- West and south exposures fail first — if two identical houses on the same street have different seal conditions, the difference is usually which way the driveway faces.
- Hardening, not tearing — the seal that fails here holds its shape. Any advice built around inspecting for damage will pass a seal that stopped working a year ago.
- Hot slab grabs soft rubber — before a seal hardens it goes through a phase of sticking to the concrete on summer afternoons and peeling loose as the door lifts. That's not damage, but it does tug the astragal along its channel over time.
- Monsoon silt packs the retainer — the fine dust that comes with a haboob works into the channel and holds moisture against the aluminum, which is why an old retainer often needs twenty minutes of cleaning before new rubber will slide.
- The gap costs more here than elsewhere — an eighth of an inch of daylight is a path for 115-degree air into an attached garage, blown dust, and the small hard-shelled traffic that follows both.
Getting more life out of the next one
You can't beat the sun, but you can stop the avoidable half of this.
- Thumb-test the seal every spring before the hot months rather than after. It takes ten seconds and it's the only inspection on this page that actually predicts anything.
- Rinse the bottom edge when you wash the door — grit trapped between rubber and concrete acts like sandpaper on every cycle, and it's the part everyone skips.
- Keep the retainer channel clear with a brush a couple of times a year, particularly after dust season. Packed silt shortens the next seal's life before it's even fitted.
- Sweep the slab under the door before closing it for the day — screws, gravel and wire ties are what turn a hardened seal into a torn one.
- Choose a bulb profile if your floor isn't flat rather than fighting an uneven slab with a stiffer flat seal. More squash means more tolerance for the concrete.
- Reset the opener's down travel after any seal change and finish with the 2x4 contact test, so the new rubber isn't quietly being crushed on every close.
Where an unattended seal ends up
It's a small part with a long tail of consequences, and the sequence is predictable.
The last two steps are the reason we mention travel limits on a page about rubber. A seal job that ends at the seal tends to produce a second phone call a week later.
What we look at on a seal call
A bottom seal is a small part, so the visit is mostly about confirming the seal is genuinely the reason for the gap rather than the visible symptom of something else.
- Compression-test the existing astragal along its full width, not just in the middle
- Check the light pattern with the door closed to separate rubber failure from floor contour
- Straightedge the slab across the opening and note any dip or lip
- Inspect the retainer for straightness, packing, corrosion and loose fasteners
- Check how the bottom seal meets the vertical jamb seals at both corners
- Fit a profile matched to the retainer and to how flat the floor actually is
- Reset the opener's down travel limit for the new seal thickness
- Run the contact reversal test with a 2x4 and show you the result
You'll get a written quote before any work starts.
When you want it handled rather than diagnosed, this is the page for it: weather stripping and bottom seal replacement.
What drives the cost
This is one of the least expensive repairs on a garage door. What moves the number is what else the visit turns up.
- Door width Astragal is priced by the foot, so a double door takes roughly twice the material of a single.
- Seal profile A simple T-style is the cheapest option. A deep bulb seal for an uneven floor costs more, and it's usually worth it.
- Condition of the retainer A clean channel takes minutes. A packed, corroded, or kinked one is the difference between a seal job and a seal-plus-channel job. We'll tell you which one you have before starting the weather stripping and bottom seal replacement.
- Whether a threshold is the better answer Where the slab has dipped, a bonded floor threshold does what no seal can. It's a bigger material cost and it lasts.
- Whether the opener needs resetting afterwards New rubber changes where the door closes. Resetting the down limit and re-testing reversal is part of doing the job properly rather than an add-on.
You'll get a written quote before any work starts. If the door is due anyway, our full tune-up is $39.99 — same price in every city we serve.
Still stuck? We’ll come take a look.
Same-day service is our standard across Mesa, Gilbert, Chandler, Queen Creek, Scottsdale, Phoenix, and the rest of the Valley.
Due for a check-up while we’re out? Our full tune-up is $39.99 — same price in every city we serve.
Questions we get asked about this
Press it hard with your thumb and let go. Rubber with life in it dents and springs back. A spent seal barely moves or stays dented, and it feels like hard plastic rather than rubber. Do that at both ends and the middle. Looking for tears will mislead you here, because the seal that fails in Arizona usually looks completely intact.
Two to four years on most doors around Mesa and Chandler, against eight to ten in a mild climate. Direct sun plus a slab that stays hot into the evening drives the plasticizers out of the rubber. West- and south-facing doors are at the short end. Check yours yearly rather than waiting for it to look bad.
Because a seal doesn't work by being present, it works by squashing. Once the rubber has hardened it stops deforming against the concrete, so it only touches at the high spots and leaves a thin even line of light everywhere else. That's the standard failure here and it's invisible to a visual inspection.
Yes, and it's one of the cheapest things on a door. That gap is a direct path for 115-degree air, blown dust, monsoon water and scorpions into a space that's usually attached to the house. It also lets conditioned air out if the garage shares a wall or ceiling with living space. For a garage that shares a wall with the house, that alone tends to justify the weather stripping and bottom seal replacement.
The industry's own answer is that it needs fixing. DASMA publishes a residential garage door checklist for home inspectors and consumers, TDS #167, and item 12c asks flatly: “Does the door fully close and rest on the floor with no gap?” It's a pass-or-fail question, and the checklist's instruction is that a No means stopping and calling a trained door systems technician. So a line of daylight isn't a cosmetic detail you can weigh up — it's a documented fail. On the pest side the guidance lands in the same place: University of Arizona Extension's standard for exterior doors is that “no outside light should be visible underneath” when you look from inside at floor level.
By air infiltration through the installed assembly, not by the seal on its own. DASMA's TDS #187 says air infiltration values are “reported as the volume of air moving per second per square foot of door area” and “should be determined in accordance with ANSI/DASMA 105.” Worth knowing because it means a sealing claim is about the whole door as fitted — a good strip of rubber on a door with an open corner doesn't buy you the number.
The astragal is the rubber strip — the wear part, replaced periodically. The retainer is the aluminum channel it slides into, mounted along the bottom edge of the door. The retainer normally lasts the life of the door unless it's been struck. Most replacement confusion comes from advice that doesn't separate the two.
It's a hands-on job with the door closed, and it involves sliding rubber out of a channel and new rubber back in — no springs, cables or brackets. We publish the full procedure on our weather stripping page. The one thing to know going in is that a stiff old seal in a dirty channel can take real effort to remove, and cleaning the channel is usually most of the work.
No, and you shouldn't. The astragal slides out the end of the retainer channel; nothing about that requires touching the corner brackets. Those brackets carry the full pull of the lift cables and are labeled from the factory because of it. If a set of instructions has you removing bracket bolts, it isn't describing a seal replacement.
Because new rubber is thicker and firmer than the flattened strip it replaced, so the door now meets the floor slightly earlier than the opener expects. The opener keeps driving toward its old stopping number, loads up against the seal, and either strains or reverses. Reset the down travel limit, then re-run the 2x4 contact test.
Depends on your floor. A T-style is fine on flat concrete. A bulb profile is hollow and collapses further, so it takes up more variation — which makes it the better choice on a slab with a dip or a slope. Either way, the beaded edges have to match the slots in your existing retainer.
Probably not. A hardened seal fails evenly because the rubber is equally stiff along its length. A gap concentrated at one corner points at either a low spot in the slab or a door hanging out of level, and the second one is worth taking seriously — a door that isn't level is usually a cable or drum issue.
It closes one part of the path. Scorpions and blown dust also use the vertical seals down each side, the header seal across the top, and particularly the corners where those meet the bottom seal. Replacing only the astragal and finding nothing has changed is one of the most common complaints we hear, and it's why the perimeter is its own subject.
It's a sign the rubber is still soft, which is the good news, and it's normal on a summer afternoon here. What it does over time is tug the astragal along its channel every time the door lifts, which is one of the reasons seals here end up with bare retainer showing at one end. Keeping the slab swept helps more than you'd expect.
Where this information comes from
- DASMA Technical Data Sheet #167 — Residential Sectional Garage Door & Electric Operator Checklist — item 12c asks whether the door fully closes and rests on the floor with no gap — a pass/fail question, which is why we don't treat a daylight gap as cosmetic
- DASMA Technical Data Sheet #187 — Environmental Considerations for Exterior Doors — air infiltration is measured through the installed assembly to ANSI/DASMA 105, which is what any sealing-performance claim should be referenced against
- University of Arizona Cooperative Extension az1677 — Pest-proofing Your Home — the no-visible-light standard for exterior doors, and the recommendation of a brush or rubber seal rather than vinyl at garage door bottoms — its stated reason is cold-weather performance, which doesn't apply here
- DASMA Technical Data Sheets (full index) — the industry's own reference library for door components and terminology, including bottom seal and retainer nomenclature
- Door manufacturer bottom seal and retainer fitting instructions — profile and slot dimensions vary by manufacturer; match the beaded edge to your existing channel rather than to a generic part description
- Farnsworth service records across Mesa, Gilbert, Chandler and Queen Creek — the two-to-four-year figure is what we replace in the field here, not a published national average
Where we come out
We’re a family-run shop based in Mesa, and we cover the whole Phoenix metro. Same-day service is our standard — pick your city, or just call (602) 935-9766 and we’ll find the soonest slot that works.
Not sure if you’re in range? Give us a call — if we can’t get to you, we’ll point you to someone who can.
Want us to just take care of it?
If you’ve worked through this and you’d rather have someone who does this every day handle it — that’s us. Tell us what your garage door is doing and we’ll come diagnose it properly.
- Same-day service is our standard
- Family-owned right here in Mesa
- Straight answers — we’ll tell you if it’s not worth fixing
- Written quote before any work starts