Replace Bay Window With Regular Window — Bay Out, Wall Framed Flat
The bay seat is cold all winter, the little roof has leaked, or the projection is in the way, and you would rather have a flat window in a flat wall.
Reply within one business day. Or call / text 763-204-2099.
To replace a bay window with a regular window, JMB Builders removes the bay with its roof, seat and support, frames the wall flat with sheathing and wrap, sets a picture, casement or double hung window flashed into the new wall, and patches siding, drywall and trim as separate quote lines, with the permit pulled when required. Twin Cities metro, priced per opening. Send photos and we reply within one business day, or book a free in-home estimate.
- Priced per opening, patch lines itemized
- Bay roof, seat and cables removed
- Permit pulled when the city requires it
Bays come out for a few reasons. The seat is cold because there was never real insulation under it. The small roof leaks into the wall. The unit has dropped off its cables. Or the room is being redone and the projection is in the way. A new bay fixes the window but keeps all of that; going flat removes the roof, the seat and the cables for good.
There are two kinds of bay, and they are different jobs. A window bay hangs off the wall: the unit carries its own seat and head board, and behind it is a normal rough opening with a header. Removing it leaves that opening, which we frame down to the new window. A framed bump-out has its own floor, walls and roof built from lumber, sometimes cantilevered; making that flat means taking it apart and closing the floor and wall, and it is quoted after we see it.
The patch is what you notice later. Outside, the wall gets sheathing, house wrap and flashing, then siding woven into the existing courses. If your siding is no longer made, we talk through the closest profile or running a section to a corner or trim break. Inside, drywall is patched and the new window is cased to match the room. Painting is quoted as a separate line, or leave it primed and caulked and 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 763-204-2099.
What you supply
- Photos of the bay inside and out, the roof over it and the underside from outside
- The window you want in its place: picture, twin casements, double hung or a mulled combination
- A siding decision: closest match, or re-side to a corner or trim break
- Paint colors inside and out, or plan to paint it yourself
- Furniture moved out of the bay and well back from the wall
What JMB supplies
- In-person measure, with the bay's support, roof and framing checked before ordering
- The new window, ordered to the framed-down opening
- Removal and haul-away of the bay unit, roof, seat, head board and cables
- Wall framing, sheathing, house wrap, sill pan and flashing tape
- Exterior siding and trim patch as its own quote line
- Interior drywall patch, casing and stool as its own quote line
- Plastic and drop cloths down; the wall is closed and weathertight before we leave each day
- The permit, pulled by us when the city requires one
How it is priced: per opening
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- Window bay hung off the wall vs. a framed bump-out with its own floor
- Bay roof: shingled, copper or metal cap, or tucked under the eave
- New window width compared with the old rough opening
- Siding type and whether a matching profile is still made
- Rot in the wall framing, sill plate or header found when the bay comes out
- Interior finish: drywall patch, new casing, flooring where a bump-out floor closes
- Window brand, size and glass package
Send a photo of the bay from the yard showing its roof and the siding on both sides. That shows most of what the patch involves.
How long it takes
A window bay to a flat window with siding and drywall patched: about two to three working days, plus drywall drying and paint. A framed bump-out takes longer and is scheduled after the measure.
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
Bay to picture window
One large fixed pane in the flat wall. The most glass and the least frame, and nothing to crank. Pick this when the bay was for the view, not for air.
Bay to casements or a combo
Twin casements, or a picture window with a casement on each side, mulled into one unit. Keeps the width of glass the bay had and adds fresh air.
Framed bump-out
A bay with its own floor and walls. Taking it flat means removing the floor framing and closing the wall and the floor line, so it is quoted after we look inside and out.
Replace Bay Window With Regular Window — Bay Out, Wall Framed Flat: questions, answered
How hard is it to remove a bay window and close up the wall?
For a window bay hung off the wall, it is a framing and patch job: the bay comes off, the opening is framed down for the new window, and the wall is sheathed, wrapped, flashed and sided. It runs a few days. A bump-out with its own floor is a bigger job and is quoted after we see it.
Do I need a permit to remove a bay window?
Changing an exterior wall and the framing around an opening is permit work in many Twin Cities cities. We check with your city and pull the permit when one is required. It shows up as a line on the quote.
Does the header change when a bay window comes out?
Usually not. A window bay sits in a rough opening that already has a header, and the flat window goes into that opening or a smaller one framed down inside it. If you want the opening wider, the header is sized for the new span, by an engineer when the span calls for it.
Will the siding match where the bay window was?
If your siding is still made, new pieces are woven into the existing courses. Older siding may have faded or been discontinued; then we look at the closest profile or re-siding that wall to a corner or trim break. We show you the options before the order goes in.
Is a flat window warmer than a bay window?
A flat window sits in the insulated wall, with no seat, head board or small roof hanging outside it, so there are fewer cold surfaces and fewer joints to leak. How warm the window itself is depends on the unit and glass you pick. A cold bay seat is one of the most common reasons people go flat.
Should I put in a new bay or replace it with a flat window?
If you like the seat and the projection, a new bay with proper support, insulation and flashing keeps them. If the bay was always cold, leaked, or is in the way, going flat removes those parts. We can price both on one visit; the like-for-like bay is on its own 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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