Garage Window Replacement — Attached and Detached Garages
The garage windows are original: single-pane, painted shut, the sill soft and the glazing putty gone.
Reply within one business day. Or call / text 763-204-2099.
Garage window replacement is a small job most window companies skip: one to four old single-pane wood or aluminum windows in an attached or detached garage, often with a rotted sill. JMB Builders replaces them across the Twin Cities metro with new-construction units with a nailing fin, flashed into the wall and trimmed to match the garage. One window is worth a call. Priced per window, quoted from photos.
- Priced per window
- One window is not too small
- Rotted sills and framing repaired
Garage windows are usually the last original windows on the property. In a detached garage they are often single-pane wood sashes or old aluminum sliders set straight into the studs, with siding nailed right over the framing and no housewrap. They rot at the sill, leak at the head and rattle in the wind. Most window companies do not want a one- or two-window garage job. We do.
Because many garage walls have no sheathing and no finished interior, the install is different from a house window. The old window and any rotted sill or framing come out, the opening is squared, a sill pan and flashing tape go in against whatever the wall has, and a new-construction window with a nailing fin is set, sealed and trimmed outside. Inside, an unfinished wall gets a simple wood frame around the jamb; a finished, heated garage gets jamb extensions and casing like the house.
The glass is your call. Insulated glass is the standard on new vinyl windows and makes sense in a heated or attached garage. Obscure glass keeps tools and cars out of view from the alley. The garage service door is its own page, and both can be done on one trip.
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
- Photos of each garage window inside and out, with a close-up of the sill
- Whether the garage is heated, insulated or finished inside
- Glass preference: clear or obscure, and window style
- Siding color or trim color to match
What JMB supplies
- The windows, ordered to the measured openings
- Removal and haul-away of the old windows
- Rotted sill or framing replaced, quoted before we continue
- Sill pan, flashing tape, low-expansion foam and sealant
- Exterior trim to match the garage, or capping, and siding patched around the opening
- A simple interior frame on an unfinished wall, or jamb extensions and casing on a finished one
- Photos of the finished windows 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:
- Number of windows on one trip
- Rot at the sill and the framing around the opening
- Siding type: lap siding, vinyl, steel or stucco on the garage
- Changing the opening size to fit a standard window
- Glass: insulated, obscure or tempered where required
- Interior: unfinished studs vs. finished drywall and trim
Send a photo of each window from outside, one from inside, and a close-up of the sill. Add the garage service door if you want both quoted.
How long it takes
One or two garage windows: half a day to a day. Rotted framing or a resized opening adds time.
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
Detached garage, unfinished inside
Old sash out, framing repaired, nail-fin window set with a pan and flashing, trimmed outside, and a simple wood frame inside around the jamb.
Attached or heated garage
Treated like a house window: insulated glass, foam and air seal around the frame, and jamb extensions and casing on the finished wall.
Resize to a standard window
Old garage openings are often odd sizes. Framing the opening to a standard size can cost less than a custom window. We price both.
Window and service door together
The side door is often as old as the windows. Doing both on one trip shares the setup and the trim work.
Garage Window Replacement — Attached and Detached Garages: questions, answered
Do you replace just one garage window?
Yes. A single garage window is a normal job for us. It is priced per window, and doing two or three on the same trip spreads the setup across them. Send a photo of each window and the sill.
What kind of window goes in a detached garage?
Usually a vinyl new-construction window with a nailing fin, in a slider, single-hung or fixed style. Insulated glass is standard on most new units. Obscure glass is a good choice where the garage faces an alley or a neighbor.
Can you fix a rotted garage window frame?
Yes. The old window comes out, the rotted sill and any soft framing below or beside it are cut out and replaced, and the new window goes in on a sill pan. The repair is shown and quoted before we continue.
Do garage windows need to be insulated?
Not in an unheated detached garage, though most new windows come with insulated glass anyway. In a heated or attached garage, insulated glass and a foamed, sealed frame make a real difference to the heating bill and to frost on the glass.
Can you put a window in a garage wall that does not have one?
Yes. The siding is cut back, a header goes in over the new opening, the window is set and flashed, and the siding is patched around it. Garage walls next to the house can have fire separation rules, so we check the location first.
Can you replace the garage windows and the side door at the same time?
Yes. The service door is its own line on the quote, but doing it on the same trip shares the setup and the trim matching. The door work is covered on the garage service door page.
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 windows pages
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Window Replacement & Installation near you
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