Steel Casement Window Replacement — Old Metal Crank Windows
The old steel crank windows in your 1940s house are rusted, frost over in winter and the cranks have long since stopped turning.
Reply within one business day. Or call / text 763-204-2099.
Steel casement window replacement takes out the 1930s to 1950s metal crank windows set in plaster walls or masonry and puts in insulated casements. JMB Builders cuts the steel frame loose from its anchors, protects the plaster, builds a wood buck where the opening needs one, and sets, flashes and trims the new window across the Twin Cities metro. Priced per window, quoted from photos, with a reply within one business day.
- Priced per window
- Steel frames cut loose, plaster protected
- Wood buck built where the opening needs one
Steel casements went into a lot of Twin Cities houses from the 1930s into the 1950s: cottages, Tudors, early ramblers, often with small panes held by thin steel bars. The steel frame carries cold straight through, so frost builds on the inside in winter. Rust swells the frame until the sash no longer closes, the glazing putty falls out, and the crank operators seize.
The frames were usually anchored into the wall with steel clips or screws into a wood buck, and in masonry walls they were set right into the mortar. Inside, the plaster often returns straight to the steel frame with no wood trim. That is what makes the removal slow: the frame is cut loose in pieces so the plaster return and the brick around it stay intact as far as possible.
Where the steel sat in masonry, a treated or PVC-wrapped wood buck is built in the opening and sealed to the brick. The new casement is set in the buck, foamed, flashed and sealed, then the inside is finished with new jamb extensions and casing or a patched plaster return. Steel windows below grade are on the basement window page; this page is the steel windows in the rooms above it.
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 steel window inside and out, and a close-up of the inside corner where plaster meets the frame
- Your window style, color and grille choices
- Furniture and wall hangings moved away from the windows
What JMB supplies
- In-home measure before anything is ordered
- Steel frames cut loose and hauled away, plaster and masonry protected
- Treated or PVC-wrapped wood buck in masonry openings
- New casements set, foamed, flashed and sealed
- Interior jamb extensions and casing, or the plaster return patched
- Painting quoted as a separate line — or leave it primed and paint it yourself
How it is priced: per window
Quoted in writing from your photos, with a reply within one business day. What moves the number:
- Wall type: wood frame with plaster, or brick and stone
- Whether a new wood buck has to be built in the opening
- Plaster return patched vs. new jamb extensions and casing
- Ganged steel units with mullions becoming mulled casements
- Grilles to match the old divided panes
- How many windows in the same job
Send a close-up of the inside corner of one window so we can see how the plaster meets the steel.
How long it takes
Usually one to three steel windows a day, depending on the wall and how the plaster is finished. Each opening is closed up the same day.
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
Keep the plaster look
The new window sits deep in the opening and the plaster return is patched up to it, with no casing. Closest to how the room looked with the steel windows.
New wood trim
Jamb extensions and casing cover the old plaster edge. Faster to finish and easier to match to other windows in the house.
Divided-pane look
Grilles between the glass or on the glass surface give the small-pane look of the old steel windows without the cold steel bars.
Steel Casement Window Replacement — Old Metal Crank Windows: questions, answered
Can old steel casement windows be repaired instead of replaced?
Steel windows can be restored by stripping rust, replacing glass and rebuilding operators, but they stay single glass in a frame that carries cold. If the goal is a warmer room without frost on the frame, replacement with insulated casements is the usual answer.
Will replacing steel windows damage my plaster walls?
Some plaster at the return usually has to be cut or patched, because it was finished right up to the steel. We cut the frame out in pieces to keep the damage small, then patch the return or cover the edge with new trim. You choose which before the work starts.
How do you remove steel windows set in brick?
The frame is cut loose of its anchors and the mortar where it was set, without breaking out the brick around it. A treated or PVC-wrapped wood buck is then fastened and sealed into the masonry opening, and the new window is set in the buck.
What should replace a steel casement window?
Usually an insulated casement, because it opens the same way and keeps the look of the house. Vinyl, fiberglass and clad wood all work. Grilles can match the divided-pane pattern of the old steel windows.
Can a new window match the small panes of my steel windows?
Close. Grilles between the glass or applied to the glass recreate the pattern of the old steel muntins. Simulated divided lites look the closest from outside. The pattern is picked at the measure.
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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