Apartment Exterior Door Frame Rot — Jambs, Sills and Thresholds
The rear door to the parking lot will not latch, the jamb crumbles at the bottom, and the threshold rocks under every resident who walks over it.
Reply within one business day. Or call / text 763-204-2099.
Apartment exterior door frame rot shows at the bottom of the jambs and under the threshold of rear and service doors, where snowmelt and salt sit. JMB Builders either splices in rot-proof jamb bottoms or replaces the whole frame, sets a sill pan, and installs a metal threshold built for heavy traffic. Twin Cities metro to St. Cloud, priced per door; send photos for a reply within one business day, or book a free in-home estimate.
- Priced per door, splice or new frame
- Sill pan under every repaired threshold
- Metal thresholds for heavy-traffic doors
Apartment exterior doors rot from the bottom. Snow gets shoveled against them, salt and meltwater sit on the threshold, and a door that a hundred people use a day never gets its caulk redone. The jamb legs go soft at the floor, the threshold loses its support and rocks, the strike pulls out, and the door stops latching, which on a secured entry is a security problem as much as a draft.
There are two repairs. When the rot stops in the bottom few inches and the rest of the frame is sound, we cut the jamb legs above the rot and splice in rot-proof jamb bottoms, then reset the threshold on a sill pan. When the rot runs up the jamb, the brickmould is gone, or the subfloor under the threshold is soft, the frame comes out and a new frame or a new prehung unit goes in.
Either way the threshold gets a sill pan under it, and on doors with heavy traffic we install an aluminum or other metal threshold rather than a wood one. Fire-rated stair or corridor doors are a different assembly; on those we replace with labeled parts only. Before we bid a building of five or more units, we check the city's contractor licensing and permit rules for that building.
Get a written quote for this job
Three photos and a sentence is enough: a reply within one business day, or ask for a free in-home estimate. Or text the photos to 763-204-2099.
What you supply
- A list of the exterior doors with soft frames, or let us walk the building
- Keys or a contact for service and rear doors
- Whether a door can be out of service for part of a day, and when
- Your lock or access-control hardware, or a locksmith's contact if the door has card access
What JMB supplies
- A probe of every jamb leg and threshold, with photos
- Rot-proof jamb bottom splices, or a new frame or prehung unit
- Subfloor and framing repair under the threshold where it is soft
- Sill pan, flashing tape and sealant at every repaired threshold
- Metal thresholds on heavy-traffic doors
- Door rehung and adjusted to latch, weatherstrip and sweep reset
- The door secured at the end of each day
How it is priced: per door
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- Splice at the jamb bottoms vs. a new frame vs. a new prehung unit
- Subfloor, rim or framing under the threshold that is soft
- Brickmould and exterior trim around the frame
- Masonry or stucco around the frame that has to be cut and patched
- Card-access, panic or closer hardware that has to come off and go back on
- Fire-rated assemblies, which take labeled parts only
- Number of doors done in the same visit
Send a photo of each door from outside, a close-up of the bottom of both jambs and the threshold, and a photo of the hinge-side frame edge if there is a label on it.
How long it takes
A jamb splice and threshold reset typically takes part of a day. A new frame takes most of a day. The door is closed and locked at the end of each 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 reply within one business day. Prefer a look in person? A free in-home estimate is always an option.
- 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 bottom splice
Rotted bottom of each jamb leg cut out, rot-proof sections spliced in, threshold reset on a sill pan. For frames that are sound above the rot.
New frame, same door
When the frame is gone but the door slab is good. A new frame is set and the existing door rehung, with new hinges if the old ones are worn.
New prehung door
When the slab is also rotted, delaminated or dented. A new unit through ABC Supply, set on a pan with a metal threshold and new brickmould.
Fire-rated exit or stair doors
Rated assemblies keep their label: frames and doors replaced only with labeled parts, closer and latch reset. The building official decides what the door needs.
Apartment Exterior Door Frame Rot — Jambs, Sills and Thresholds: questions, answered
Can a rotted apartment door frame be repaired instead of replaced?
Often, yes. When the rot is in the bottom few inches of the jamb legs, we splice in rot-proof jamb bottoms and reset the threshold on a sill pan. If the rot runs up the jamb or into the floor under the threshold, a new frame is the right fix, and the quote says which one each door gets.
What threshold is best for an apartment building rear door?
A metal threshold set on a sill pan, sized for the door and the floor height. Wood thresholds wear and rot under heavy traffic and salt. The threshold gets sealed to the pan so water that gets past it drains out, not into the floor.
Why does the apartment back door not latch anymore?
Often because the bottom of the frame has rotted and dropped, which lets the jamb move and pulls the strike out of line. Hinge screws stripped out of soft wood do the same thing. A strike adjustment will not hold until the rotted frame is repaired.
Do you work on fire-rated exit doors?
Yes, with labeled parts only. Stair and some exit doors are rated assemblies, and splicing wood into a rated steel frame is not an option. We replace the frame or door with labeled parts and reset the closer and latch; the building official decides what each door needs.
How long is the door out of service?
Typically part of a day for a splice and most of a day for a new frame. The door is closed and locked every night. We schedule entries and exits with you so residents always have another way in and out.
Can you put our card reader and closer back on the new frame?
We remove and reinstall closers, panic bars and standard locks. Card readers and electrified hardware are disconnected and reconnected by your access-control company or a licensed electrician; we coordinate the day with them.
Recent JMB work, from our job log
59 installs recorded across 30 Twin Cities communities since Dec 2025. Window and door installs for homeowners and the builders we work with. Counts come straight from our job log; no customer names.
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Read morePage reviewed October 9, 2026 · JMB Builders LLC, MN license BC809005 · All apartment buildings pages
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