Skylight Replacement — Leaking and Fogged Skylights Swapped Out
A skylight that drips in a thaw, fogs between the panes or has a yellowed dome — replaced with a new unit and new flashing, on its own or while the roof is being done.
JMB Builders does skylight replacement and leaking skylight repair on asphalt shingle roofs across the Twin Cities metro. We pull the old unit, check the curb and the sheathing, set a new deck-mounted or curb-mounted skylight with the manufacturer's flashing kit and ice and water membrane, and reshingle around it. Priced per unit, quoted from your photos within one business day, on its own or with a reroof.
- Priced per unit, flashing kit included
- Deck-mounted and curb-mounted skylights
- Quote from photos in 1 business day
- Licensed MN contractor BC809005
Most skylight leaks are flashing, not glass. The old step flashing was face-nailed, the head flashing is buried in roof cement, or the unit was set on a site-built curb with no counter flashing and thirty years of caulk. Ice dams find those spots first because meltwater backs up above the skylight and sits against the top flashing for weeks. When the skylight itself is also old (a plastic dome gone yellow, a fogged double pane, a rusted frame) the right fix is a new unit with the flashing kit made for it.
Modern skylights come as deck-mounted units that sit flat on the sheathing with their own step and head flashing, or curb-mounted units that sit on a framed curb and are flashed at the curb. We replace like with like where the opening allows, and we can change a dome on an old curb to a flat glass unit on the same curb when the size matches. The membrane goes around the opening and up the curb before anything else, and the shingles are woven back into the new flashing so there is no roof cement anywhere in the system.
Skylights are best replaced during a reroof, when the shingles around them are already off. But they do not have to wait for one. A single skylight can be swapped on a sound roof in a morning.
What you supply
- Photos of the skylight from inside, from the yard, and from a ladder if you can, showing the flashing and the shingles around it
- The brand and size label on the old unit if you can find it (usually on the frame inside)
- Your choice of fixed, manual-vent or solar-vent unit, or we recommend one from the photos
What JMB supplies
- The new skylight: fixed, venting or solar-venting, deck- or curb-mounted to fit the opening
- The manufacturer's flashing kit for the unit and roof type, plus ice and water membrane around the opening
- A new curb, or repair of the existing one, when the old curb is rotted or undersized
- Sheathing repair around the opening where the leak has softened it
- Shingles lifted, woven back into the new step flashing and replaced where brittle
- Interior cleanup at the shaft; drywall and trim repair at the light well quoted as its own line
- Photos of the flashing before the shingles go back, in your job folder
How it is priced: per unit
Quoted in writing from your photos within one business day. What moves the number:
- Same-size swap into the existing opening vs. resizing the rough opening for a different unit
- Fixed vs. venting vs. solar-venting skylight
- Deck-mounted vs. curb-mounted, and whether the curb needs to be rebuilt
- Roof pitch and height, and how far the skylight is from the eave
- Sheathing or rafter repair where the leak has been running for a while
- Several skylights on the same visit share the setup and cost less each
- Interior light well drywall and trim repair added as its own line
A photo of the label inside the frame gets us the exact replacement size. Without it, send the inside frame measurements and we match it from those.
How long it takes
One same-size skylight: about half a day. Two or three in a day. Add time when the curb or sheathing needs rebuilding or the opening is resized.
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
Same-size deck-mounted replacement
The most common job: the old unit comes out, a new deck-mounted skylight of the same size sits on membrane and gets the maker's step and head flashing kit, and the shingles are woven back. No interior work needed beyond cleanup.
Curb-mounted and dome replacements
Old plastic bubble domes usually sit on a site-built curb. A new flat glass curb-mounted unit fits the same curb when the size matches; if the curb is rotted or too low, we rebuild it and flash it with membrane and a proper counter flashing.
Fixed to venting upgrade
Swap a fixed unit for a manual or solar-powered venting skylight in the same opening for a bathroom or a hot upstairs room. Solar units need no wiring; a hardwired one goes through an electrician.
Skylights with a reroof
When the roof is being replaced, every skylight gets new flashing at minimum, and replacing an old unit at the same time is the cheapest it will ever be. We include the skylight line on the roof quote.
Skylight Replacement — Leaking and Fogged Skylights Swapped Out: questions, answered
Can a skylight be replaced without replacing the roof?
Yes. We lift the shingles around the opening, remove the old unit and flashing, set the new skylight on ice and water membrane with its flashing kit, and weave the shingles back in. On a roof with shingles that are still flexible this leaves no trace. If the shingles are brittle and crack when lifted, we replace the courses around the skylight with matching shingles and tell you the roof is getting close.
Why is my skylight leaking?
Usually the flashing: caulked or cemented head flashing, face-nailed step flashing, or an old curb with no counter flashing. Ice dams push water up under the top flashing every spring. Sometimes it is condensation, not a leak, which shows up as drips in cold weather from a single-pane dome or a poorly insulated shaft. Photos of the inside stain and the outside flashing usually tell us which one it is.
My skylight is fogged between the panes; can it be repaired?
The seal between the panes has failed and the glass cannot be resealed. On some units the glass can be replaced in the frame, but on most skylights past a certain age the frame and flashing are due at the same time, so a new unit with a new flashing kit is the better fix. We check whether the manufacturer offers replacement glass for your model before quoting a full swap.
What is the difference between deck-mounted and curb-mounted skylights?
A deck-mounted skylight sits directly on the roof sheathing with its own flange and a step-flashing kit; it is lower profile and the usual choice on a shingle roof. A curb-mounted skylight sits on a framed box a few inches tall and is flashed at the curb; it fits an existing curb, a low-slope roof or a large opening. We match the new unit to the opening you have.
Should I replace my skylights when I replace my roof?
If they are more than fifteen or twenty years old, fogged, plastic, or have ever leaked, yes. The shingles are already off, so the extra cost is mostly the unit itself, and the new flashing kit ties into the new roof. New skylights that are sound get new flashing during the reroof either way.
Do you fix the drywall inside the skylight shaft?
Yes, as its own line on the quote. A leak usually stains or softens the drywall in the light well, and a new unit sometimes changes the opening slightly. We patch and paint the shaft, or trim it out in wood if you want a finished look. That interior finish work is described on our skylight shaft trim-out page.
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 roofing pages
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