Modular Home Window Replacement — Set on a Foundation, Not a Mobile
Your house came in two or three sections on trucks and sits on a real foundation, and the first company you called assumed it needed mobile home windows.
Reply within one business day. Or call / text 763-204-2099.
Modular home window replacement is a regular residential job: a modular house is built in sections in a factory, set on a permanent foundation and framed with standard walls, so it takes standard replacement windows, not mobile home sizes. JMB Builders replaces modular home windows across the Twin Cities metro, insert or full-frame, with the factory flashing checked. Priced per window, quoted from photos or at a free in-home estimate, with a reply within one business day.
- Priced per window, standard residential units
- Not mobile-home windows: standard sizes and flanges
- Factory house wrap and marriage wall checked
A modular home is a stick-framed house built in sections in a factory, trucked to the lot and set on a basement or crawl-space foundation with a crane. Once the sections are joined and the roof is finished, it is a conventional house: wood studs, sheathing, house wrap, drywall, and windows with a nailing flange set in the wall at the factory. It is not a mobile or manufactured home, which is built on a steel chassis to a different standard and takes windows of its own sizes.
The confusion costs modular owners time, because installers who hear factory-built assume the wrong thing. Modular windows are standard residential units in standard sizes, and the ones the factory installed are often builder-grade vinyl, so fogging and failed balances show up around the fifteen-to-twenty-year mark. They are replaced the same way as in any site-built house, as inserts in a sound frame or full-frame with the siding opened around the opening.
Two things are worth checking that a site-built house does not have. The factory wrapped and flashed the windows before the sections shipped, and the quality varies by plant, so the flashing is looked at when the siding is opened. And the marriage wall, where the sections meet, sometimes puts a window close to a joint that moved during set; that opening is measured with care. 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
- Your pick of window style, exterior color and glass
- The modular manufacturer and year if you have the paperwork, which can tell us the factory window brand
- Photos of each window from outside with the siding in frame, one from inside, and a close-up of a sill
- Your paint color if you want us to finish the interior trim
What JMB supplies
- In-home measure of every opening before anything is ordered
- The windows, standard residential units ordered to size
- Old units out and hauled away
- Factory flashing checked when the siding is opened; redone where it is short or missing
- Sill pan, flashing tape to the house wrap and low-expansion foam on full-frame installs
- Siding unzipped and relocked, or trim boards reset, to suit the siding type
- Interior stops, stool and casing, or jamb extensions on a drywall return
- 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:
- Insert in a sound frame vs. full-frame with the siding opened
- Siding type: vinyl, LP SmartSide or steel each take different trim work
- Factory flashing that has to be redone when found short
- A window near the marriage wall that needs a custom size
- Glass package, grilles and exterior color
- Number of windows in the job
Send one photo of each window from outside with the siding in frame, one from inside, and a close-up of a sill. Include the modular builder's name and year if you know them.
How long it takes
A modular home of ten to fourteen windows: two to three days, like any stick-built house of that size. Every opening is closed up each night.
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
Insert in the factory frame
Where the factory vinyl frame is sound and square, the new unit sets inside it, the interior trim stays and the exterior gap is covered with a trim strip. The fastest route.
Full-frame, siding opened
The siding around the opening is unzipped or the trim boards pulled, the old unit comes out, the opening is flashed to the wrap with a sill pan and the siding goes back. The right call when the factory flashing was short or the frame has failed.
Window at the marriage wall
An opening within a foot or two of where two sections meet. Measured at several points, because the joint can rack a little during set, and ordered to fit as found.
Whole house, one order
Every window in the house in one order and one color, so the factory mix of units becomes one matched set. The second and later windows cost less than the first.
Modular Home Window Replacement — Set on a Foundation, Not a Mobile: questions, answered
Do modular homes use regular windows or mobile home windows?
Regular residential windows. A modular home is stick-framed in a factory and set on a permanent foundation, and its walls are the same as a site-built house, so the windows have standard nailing flanges in standard sizes. Mobile and manufactured homes are built on a chassis to a different standard and take their own window sizes. If an installer tells you a modular needs mobile home windows, they have the wrong house.
Is window replacement in a modular home any different from a regular house?
Barely. The windows, the install and the trim are the same. The two differences are the factory flashing, which varies by plant and is checked when the siding is opened, and the marriage wall where the sections meet, which can put a window near a joint that moved slightly during set. Both are handled at the measure.
Why did the windows in my modular home fail so early?
Most modular plants install a builder-grade vinyl window, the same kind in a lot of site-built houses of the same years. Those units fog when the glass seal fails and the balances wear out around fifteen to twenty years. It is the window, not the house. The replacements are a step up in glass and frame, and they go in the same openings.
Can I tell if my house is modular or manufactured?
A modular home sits on a basement or crawl-space foundation with no chassis under it, has standard-height ceilings and standard-size doors and windows, and has a state or local building label, often inside a kitchen cabinet or near the electrical panel. A manufactured home has a steel frame under the floor, a federal data plate and a red certification label on the outside. If you are unsure, send a photo of the foundation and we will tell you.
Should the factory flashing on a modular home be redone when the windows are replaced?
If it is short or missing, yes, and that is only known when the siding around the opening is open. Some plants do it well and some do the minimum. On a full-frame install the new window gets a sill pan and flashing tape to the house wrap regardless. On an insert the factory flashing stays, which is fine where it is doing its job.
Can new windows in a modular home be a different style from the factory ones?
Yes. The openings are standard, so a slider can become a casement or a double hung can become a slider, within the same frame size. Bedroom windows have to keep the clear opening the code calls for, so a style change there is checked before ordering. Grilles and colors are your pick.
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 10, 2026 · JMB Builders LLC, MN license BC809005 · All windows pages
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