Window Company Didn't Do Trim? We Finish Replacement Windows
The new windows are in and they look great from outside. Inside there is foam, a gap and no trim, and the window company says that was not part of the job. It is part of ours.
The window company didn't do trim — most replacement installers stop at foam and a bead of caulk. JMB Builders finishes the inside of replacement windows across the Twin Cities metro: we fill and insulate the gap, add jamb extensions or a new stop where the new frame sits shallower than the old, then install casing, stool and apron to match the rest of the house. Priced per window, quoted from photos within one business day.
- Priced per window
- Insert and full-frame replacements
- Quote from photos in 1 business day
- Licensed MN contractor BC809005
Most window companies sell windows and install windows. Interior trim is a different trade to them, so the contract says trim by others or interior finish not included, and the homeowner does not notice until the crew is gone. What is left depends on the install. With an insert (pocket) replacement, the old jambs and casing usually stay, and there is a strip of foam or a gap where the new, smaller frame meets the old wood. With a full-frame replacement everything came out, and the opening is bare framing, foam and drywall edges.
JMB Builders does interior trim after new windows across the Twin Cities metro, and we do it for window companies too, so we have seen every version of what gets left behind. We finish the gap properly — foam trimmed flush, backer rod where it is needed — then extension jambs if the new frame sits short of the wall, a new stop or filler where the old jambs stayed, and casing, stool and apron to match the rest of the house. The room looks like the windows were always there.
What you supply
- A close-up of one window showing the gap or foam, and a wide shot of the room
- The window company's paperwork if it says insert or full-frame (a photo of it is fine)
- A photo of a window or door in the house that still has its trim, so we match the profile
- Any old casing the installer saved, if you want it reused
- Your paint or stain color, if we are finishing it; the trim goes in primed and caulked, or sanded for stain
What JMB supplies
- Low-expansion foam and backer rod to finish the gap between frame and framing
- Stop or filler strips where the new frame sits inside the old jambs
- Extension jamb stock for full-frame openings, ripped to your wall depth
- Casing, stool and apron in a matched or standard profile
- Shims, fasteners, filler and paintable caulk
- Removal of loose old trim and haul-away
- Photos of every finished window in your job folder
- Painting or staining when you want it done, quoted as its own line
How it is priced: per window
Quoted in writing from your photos within one business day. What moves the number:
- Insert replacement (old jambs stay, gap gets stopped and cased) vs. full-frame (complete trim-out)
- Reusing old casing vs. new casing
- Matching an older profile that is no longer stocked, common in pre-1960 homes
- Stain-grade work to match existing woodwork vs. paint-grade
- Damage found behind the trim — drywall cut back too far, or rot at the old sill
- Patio doors and large mulled units, which count as bigger openings
- Number of windows finished in one visit
Send the close-up with a tape measure across the gap. If you know whether the install was insert or full-frame, say so; if not, the photo tells us.
How long it takes
Insert replacements with the old casing kept: several windows in a day. Full-frame openings that need jambs, casing and stool: a full main floor in a day or two.
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 quote within one business day. We only come out to measure first when the job needs a tape measure — no pressure, no games.
- 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 replacement — stop and re-case
The old jambs stayed. We foam and trim the gap, add a stop or filler strip so the new frame meets the old jamb cleanly, re-set or replace the casing, and caulk the joint. Fast, and it is the most common version of this job.
Full-frame replacement — complete trim-out
Everything came out with the old window. We install extension jambs to the wall depth, then casing, stool and apron. This is the same work as trimming a new-construction window.
Match the trim in an older home
Pre-war and mid-century homes often have casing profiles nobody stocks. We source the closest match, or rework stock profiles, so the new window trim reads the same as the rest of the room.
Switch to drywall returns
If the old casing is gone and you want the trimless look, we can build clean drywall returns at the new windows instead of trim. That job has its own page; ask and we quote both.
Window Company Didn't Do Trim? We Finish Replacement Windows: questions, answered
Why didn't the window company do the interior trim?
Because most of them do not do finish carpentry. Their crews are set up to pull windows and set windows, and the contract usually says interior trim by others, which nobody reads until afterward. Some will re-nail the old casing if it survived; most will not. It is not a mistake on their part, but it does leave you with an unfinished window. JMB Builders finishes that inside work, and we do it as a subcontractor for window companies too.
There is foam and a gap around my new windows. What should be done with it?
The foam is doing its job as insulation and air seal, but it is not a finish. We trim it flush, add backer rod and sealant anywhere the gap is wide, and then cover it. On an insert replacement that means a stop or filler strip and casing. On a full-frame replacement it means extension jambs and casing. Do not just caulk over foam; it shrinks and cracks within a season.
Can you match the trim on the rest of my windows?
Yes. Send a photo of a window that still has its casing, or a door casing, and we match the profile. Standard profiles are stocked. Older profiles get sourced from a millwork supplier or made up from stock pieces to read the same. Stain-grade matches take a little more care so the species and color line up with the existing woodwork.
The new windows are shallower than the old ones. What fixes that?
That is normal. New frames are often less deep than the wood windows they replaced, so on an insert install there is a step between the new frame and the old jamb. A stop or filler strip, ripped to the exact depth and set with an even reveal, closes it. On a full-frame install the gap is closed with extension jambs. Either way the casing lands flat afterward.
Do I hire you or does the window company?
Either. Homeowners call us directly after the windows are in, and that is most of this work. Window companies also hire us to trim out their installs so the customer gets a finished job. You do not need the installer involved; send us photos and we quote the trim on its own.
How soon after the windows go in can you trim them?
As soon as the foam has cured, which is a day. There is no reason to wait, and it is better to trim before the walls are painted or furniture goes back against them. If you know your install date, send it and we will get the trim on the schedule right behind it.
Get a written quote for this job
Three photos and a sentence is enough. You hear back within one business day. Or text the photos to 763-204-2099.
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Read morePage reviewed September 24, 2026 · JMB Builders LLC, MN license BC809005 · All window trim pages
Where we work
Window trim near you
Based in Zimmerman, scheduling across the Twin Cities metro. Closest first: