Apartment Patio Door Sill Rot — Subfloor and Rim, Priced Per Door
Tenants say the floor gives by the slider. In a building full of the same doors, that usually means more than one unit is rotted under the sill.
Reply within one business day. Or call / text 763-204-2099.
Apartment patio door sill rot shows when the old door comes out: soft subfloor, a punky rim or sill plate. JMB Builders prices the repair as a set line per door in the bid, so the owner knows the cost before the wall is opened, cuts back to sound wood, rebuilds it, and sets the new door on a flashed sill pan. Twin Cities metro. Photos get a reply within one business day, or book a free in-home estimate.
- Rot repair as a set line per door
- Photos of every rotted sill for the owner
- New door set on a flashed sill pan
A patio door that leaked for years leaves the damage under it: the subfloor goes soft, then the rim joist and sill plate start to go. In an apartment building with the same doors in every unit, if one unit is rotted, others often are too. The trouble for the owner is that nobody can price rot nobody can see.
So the bid carries rot repair as a set line per door: a defined amount of subfloor and rim, priced once, used only where the door comes out and the wood is soft. Rot beyond that is photographed and priced before we go further. The owner sees every rotted sill in the photos, filed by unit.
The repair cuts back to sound wood and replaces the subfloor; the rim and sill plate are sistered or replaced with the wall carried where needed. Then a sill pan with a back dam and flashing go in before the new door. In apartment buildings the floor between units is often part of a rated assembly; if the repair reaches into it, the building official may need to see it. 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
- Units where tenants report a soft floor or stains by the door
- Access to each unit and, if needed, the unit below
- Approval of the set rot line in the bid
- Tenant notice, sent by the owner or manager
What JMB supplies
- A set rot-repair line per door in the bid
- Photos of every opened sill, filed by unit
- Subfloor, rim and sill plate cut back and rebuilt
- The wall carried while framing at the sill is replaced
- Sill pan with a back dam and flashing under the new door
- A new door ordered through ABC Supply to the building spec
- A written note when rot runs past the set line, before more is opened
How it is priced: per door
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- How far the rot runs past the set line
- Subfloor only vs. rim joist and sill plate
- Rot reaching floor joists, which may need an engineer's look
- Flooring at the door to cut out and patch
- Ceiling access from the unit below, if needed
- Siding or brick to remove at the bottom of the opening
Send photos of the sill inside and out, any floor stains, and the ceiling of the unit below.
How long it takes
A door with rot inside the set line: typically still one working day per unit. Rot into the rim or joists can add a day; the opening is covered overnight.
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
Subfloor only
Soft plywood or boards at the sill. Cut back, new subfloor glued and screwed, then the pan and door. The common case.
Rim joist and sill plate
The framing under the wall is soft. The wall is carried, the rim and plate are rebuilt, and then the floor and door go back.
Into the joists
Rot that reaches floor joists is opened, photographed and assessed; a repair at that size may be sized by an engineer before it is built.
Apartment Patio Door Sill Rot — Subfloor and Rim, Priced Per Door: questions, answered
Why is the floor soft by the sliding door in our apartment units?
The door has been leaking at the sill, usually for years, and the water has rotted the subfloor. Old doors set without a sill pan are the common cause. If one unit has it, others with the same door often do too.
How do you price rot repair you can't see until the door is out?
The bid carries a set rot line per door, a defined repair priced once and used only where the wood is soft. Rot beyond it is photographed and priced before we go further. The owner never finds out about the extra after the fact.
Can rot repair and the new patio door be done the same day?
Usually, when the rot stays in the subfloor. Rot into the rim or sill plate can add a day, and the opening is covered and secured overnight.
What if the rot goes into the floor joists?
We stop, photograph it and tell the owner. A repair at that size may be sized by an engineer, and in an apartment building the floor between units may be a rated assembly the building official needs to see.
Will the owner see what was found under each patio door?
Yes. Every opened sill is photographed and filed by unit number, rotted or not. That shows which doors needed the set line and which did not.
Is the flooring by the patio door replaced too?
The flooring cut out at the door is patched or replaced as its own line. Matching an old floor exactly is not always possible, so the bid says what is planned.
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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