Garage Door Jamb Rot Repair & Weather Seal Replacement
The bottom foot of the garage door jamb is soft, the stop molding is curling, and you can see daylight beside the door. We replace the rot in PVC and put on a stop that actually seals.
Garage door jamb rot starts at the bottom, where the jamb sits on concrete and the weather seal traps water against the end grain. JMB Builders repairs it across the Twin Cities metro: we cut the rotted section out, replace the jamb bottom or the full leg in PVC, re-lag the track brackets to solid material, and install new vinyl stop molding with the seal built in. Priced per opening, quoted from photos.
- Priced per opening
- PVC jamb bottoms or full jamb legs
- Vinyl stop with integrated weather seal
- Quote from photos in 1 business day
- Licensed MN contractor BC809005
Garage door jambs rot for one reason: the bottom of the jamb sits on or right at the slab, and everything the driveway throws at it, snowmelt, salt, splash, sprinkler water, sits against that end grain. The old wood stop molding nailed to the face of the jamb holds the water there. A few winters in, the bottom foot of the jamb is punky, the stop is curling away, and the garage is full of leaves and mice.
The wrong fix is to cut out the soft spot, fill it and paint. The right fix is to cut the jamb back to sound wood, replace the bottom in cellular PVC that does not care about water, and hold it up off the slab a hair so it can dry. The stop molding gets replaced with vinyl stop that has the weather seal molded in, so the seal and the trim are one piece and there is no wood left for the water to find.
The part people forget: the garage door track brackets are lagged into that jamb. If the bottom brackets are screwed into rot, the track can walk and the door binds. We re-lag them into the new material and check the track is still plumb before we leave. We do not adjust springs or cables; that stays with a garage door company.
What you supply
- Photos: the bottom of each jamb, the full door from the driveway, and a close-up of the stop molding where it meets the header
- Color for the vinyl stop: white, brown, almond and tan are common stock colors
- Your paint color if you want the PVC jamb in something other than white and want us to paint it
What JMB supplies
- Removal of the rotted jamb section, old stop molding and old seal
- Cellular PVC jamb stock, spliced to the sound wood above or run the full height
- Vinyl stop molding with the weather seal built in, sides and header
- Re-lagging of the track brackets into solid material and a plumb check on the track
- Stainless or coated fasteners, PVC cement at the splice, sealant at the slab and the siding
- Photos of the finished jambs in your job folder
- Painting the new jamb when you want a color other than white, quoted as its own line
How it is priced: per opening
Quoted in writing from your photos within one business day. What moves the number:
- Jamb bottoms only vs. full-height jamb legs and the header
- Single or double garage door
- Whether the exterior casing or brickmould outside the jamb is rotted too
- Track brackets that have to be moved or re-anchored
- Framing behind the jamb that is soft once the jamb comes off
- Stop molding only, when the jambs are sound and only the seal has failed
Push a screwdriver into the jamb a foot up from the slab and tell us if it stops. If it does, this is a jamb-bottom job and we can quote it from the photos.
How long it takes
Jamb bottoms and new stop on a single door: half a day. A double door with full jamb legs and the header: a full day.
How your project works
- 1
Send photos, get a written quote
Send three photos of the space and a sentence about what you want. You get a clear, itemized quote within one business day. We only come out to measure first when the job needs a tape measure — no pressure, no games.
- 2
Pick materials, or bring your own
We help you choose profiles and materials that fit the house and the budget, or match your existing millwork exactly — or you buy the door or trim yourself and we install it. Everything is confirmed before the crew is scheduled.
- 3
Clean, precise installation
The crew shows up on time, protects floors and furniture, and installs with tight joints and consistent reveals. Photos of the finished work go in your job folder.
- 4
Walkthrough and invoice
We walk the finished work with you. If anything is not right, we fix it before we call the job done. Then one invoice, paid by check or direct deposit — no card fees, no payment links.
Situations and options
Jamb bottoms in PVC
The most common repair. We cut the rot out square, splice in PVC, glue and fasten the joint, and hold the bottom off the slab. The stop molding is replaced at the same time.
Full jamb leg replacement
When the rot runs more than a couple of feet up or the jamb was never flashed, we pull the whole leg, check the framing behind it, and run new PVC full height with the track brackets re-lagged.
Vinyl stop with weather seal only
The jambs are sound but the old stop is split, the seal is torn and the door leaks air. We pull the old stop, set new vinyl stop with the seal against the door, and seal the joint to the jamb.
Header drip cap and stop
The header is the longest piece and the most exposed. We add a continuous drip cap above the header trim and run the header stop with the seal touching the top panel.
Garage Door Jamb Rot Repair & Weather Seal Replacement: questions, answered
Why does the bottom of my garage door jamb rot?
Because it sits at the slab where the water is. Snowmelt, salt and splash from the driveway sit against the end grain at the bottom of the jamb, and the wood stop molding nailed to it holds the water there. End grain wicks it up. A jamb that was never primed on the bottom or was set right on the concrete goes first. It is the same problem as a rotted door casing, just with more water.
Can you replace just the bottom of the garage door jamb?
Yes. If the rot stops within the first couple of feet, we cut the jamb square above the rot, splice in cellular PVC of the same size, glue and fasten the joint, and hold the new bottom just off the slab so it can dry. The splice is covered by the new stop molding. If the rot runs higher or the jamb was never flashed, replacing the full leg is the cleaner job.
What is garage door stop molding and why replace it?
Stop molding is the trim on the face of the jamb that the door closes against; the weather seal hangs off it. The old style is wood stop with a rubber seal stapled on. Vinyl stop has the flexible seal molded into it, so there is no wood to rot, no staples to rust, and the seal stays put. When we repair a jamb we always replace the stop, because the old wood stop is usually what held the water against the jamb in the first place.
Do you replace the garage door weather seal on the sides and top?
Yes. The side and header seals come with the vinyl stop molding, so replacing the stop replaces the seal. We set the stop so the seal touches the door without pushing on it, which is the difference between a door that seals and one that binds. The bottom seal on the door panel itself is a garage door part and is usually a separate piece from the door company.
Will replacing the jamb affect the garage door tracks?
The vertical tracks are held by brackets lagged into the jambs, so yes, we work around them. When we replace a jamb bottom we re-lag the lower brackets into the new PVC or into the framing behind it and check that the track is still plumb. We do not touch the springs, cables or opener. If the door needs balancing after years of running on a crooked track, that is a garage door company call.
Should garage door jambs be wood or PVC?
PVC at the bottom, at minimum. The bottom of a garage door jamb is the wettest piece of trim on the house, and cellular PVC does not rot or swell there. We run the full leg in PVC when we replace the whole thing. Track brackets lag into it fine as long as the lags reach the framing behind.
Get a written quote for this job
Three photos and a sentence is enough. You hear back within one business day. Or text the photos to 763-204-2099.
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Read morePage reviewed September 24, 2026 · JMB Builders LLC, MN license BC809005 · All exterior trim pages
Where we work
Exterior trim near you
Based in Zimmerman, scheduling across the Twin Cities metro. Closest first: