Replace One Rotted Window Before It Spreads
The sill is soft when you press it, the paint is bubbling at the bottom corners, and the rest of the windows are fine.
Reply within one business day. Or call / text 763-250-3621.
Rotted window replacement for one window means the whole window comes out to the rough opening: the soft sill, jamb legs and framing under them are cut out and replaced, the opening gets a sill pan and flashing, and a new window is set and trimmed. JMB Builders does this one window at a time across the Twin Cities metro, priced per window with the window included. Photo reply within one business day, or a free in-home estimate.
- One rotted window is a welcome job
- Full frame install, rot cut out, sill pan and flashing
- Priced per window, window included
Rot in a window starts where water sits: the outside sill, the bottom corners of the jamb, and the joint where the sash meets the sill. It spreads down into the framing and the sheathing behind the siding. One rotted window usually means the window above a leaky gutter, the one on the west wall that takes the rain, or the one over a deck or roof where snow piles against it.
A rotted window is a replacement, not a patch. Filler and paint over soft wood hold for a season. An insert window set inside a rotted frame leaves the rot in the wall. The right fix is a full-frame replacement: the old window and frame come out to the rough opening, the soft wood is cut back to sound framing and replaced, the sheathing is checked, and a sill pan and flashing tape go in so the next twenty years of water run out instead of in.
Then the new window goes in. A plain white size that our supplier has in stock can be picked up for the install; a color, grille pattern or odd size is custom ordered to the opening with the lead time written on the quote. We finish the outside with capping or trim and the inside with stops or casing, primed and caulked. Painting is quoted as a separate line, or paint it yourself.
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 763-250-3621.
What you supply
- Photos of the window inside and out, with close-ups of the sill and the bottom corners of the frame
- A photo of the wall below the window and anything above it, such as a gutter or roof edge
- Your pick of style, color and glass, or ask us to match the other windows
- Paint or stain color for new trim, or leave it primed
What JMB supplies
- A look at the sill, jambs and framing at the measure, with photos of what we find
- The replacement window, in stock or custom ordered through ABC Supply
- Removal of the old window and frame to the rough opening, haul-away included
- Rot cut out and replaced in the sill, jamb legs, framing and sheathing as needed
- Sill pan, flashing tape lapped at the sides and head, shims, foam and sealant
- Exterior capping or trim and interior stops or casing, primed and caulked
- Painting quoted as a separate line, or leave it primed and paint it yourself
- Photos of the finished window in your job folder
How it is priced: per window
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- How far the rot runs: sill only, or into the jamb legs, framing and sheathing
- The window: size, style, in stock white vinyl vs. a custom ordered color or glass
- Siding, stucco or brick around the opening and how it is cut back and finished
- Interior trim kept, matched or replaced
- Second story or hard-to-reach openings
- Painting the new trim, quoted as its own line
Close-ups of the sill and bottom corners let us quote the repair from photos. If more rot shows up once the window is out, we show you before it is fixed.
How long it takes
Most single rotted windows take a day on site, longer when the framing or sheathing under the sill has to be rebuilt. An in-stock window is picked up for the install; a custom ordered one has its lead time on the quote.
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
Sill rot only
The outside sill is soft but the jambs and framing are sound. The window comes out, the sill and any soft sheathing are replaced, and the new window goes in with a pan and flashing.
Rot into the framing
The rough sill and the bottom of the studs are soft. The wall is opened at the window, the framing is cut back to sound wood and replaced, and the sheathing is patched before the new window is set.
Rot from above
Water came from a gutter, roof edge or a failed head flashing. The source is fixed as part of the job so the new window does not take the same water.
Replace One Rotted Window Before It Spreads: questions, answered
Can a rotted window be repaired instead of replaced?
Soft wood does not come back. Filler and paint hold for a season and the rot keeps moving into the framing behind it. For one rotted window the lasting fix is a full-frame replacement: the rot cut out, the opening flashed with a sill pan, and a new window set. That is what JMB Builders quotes.
Why is only one of my windows rotting?
It is taking water the others are not. Common reasons are a gutter overflowing above it, a west or south exposure that gets the weather, snow piling against it on a deck or roof, or a missing head flashing on that one opening. We find the reason and fix it as part of the replacement so the new window stays dry.
Can you put an insert window into a rotted frame?
No. An insert depends on the old frame being sound, and it would leave the rot in the wall behind the new window. A rotted window gets a full-frame replacement to the rough opening so the soft wood can be cut out and the opening flashed properly.
How far does the rot usually go?
Often just the sill and the bottom corners of the jambs. Sometimes it is into the rough sill, the bottom of the studs and the sheathing. We check at the measure and quote what we can see; if more shows up when the window is out, we show you photos before it is fixed.
Is a replacement for a rotted window in stock or custom ordered?
Either. If a common size in white vinyl fits the opening, it is often in stock and can be picked up for the install. A color, grille pattern or odd size is custom ordered and the lead time is written on the quote. Since the wall is already open to the framing, the exact size can be set when the new window is ordered.
Will the rotted wall under the window be covered up with the new window?
Not by us. Soft framing and sheathing are cut out and replaced before the new window goes in. Covering rot with a new window and trim is how the next owner ends up with a wall repair. Send photos and we reply within one business day, or book a free in-home estimate.
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 25, 2026 · JMB Builders LLC, MN license BC809005 · All windows pages
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