Skylight Replacement Cost in Wisconsin: What to Expect

What skylight replacement actually costs in the Madison market

These are installed prices: the unit, the manufacturer's flashing kit, labor, and cleanup. Where your quote lands depends on size, roof pitch, and how much interior work is involved.

That flat-roof line surprises people. On a low-slope section over a 1980s family-room addition you are not just setting a skylight, you are rebuilding a curb, terminating EPDM or TPO membrane up the sides, and fabricating metal counterflashing. Two or three units on a flat section can pass $6,000 total, and any contractor who will not say that up front is going to hand you a change order later.

Add-ons that move the number:

Anyone who quotes a skylight over the phone without knowing the unit size, the pitch, or the condition of the shaft is guessing.

Why skylights leak (and why some of them are not leaking at all)

Four failure modes cover nearly everything we see in Dane County.

Failed flashing kit. The flashing, not the glass, is what keeps water out. Old aluminum step-flashing kits from the 70s and 80s corrode, the sealant under the head flashing dries out, and water walks in behind it. We see this constantly on west-side Madison homes from the cedar-shake era, where a skylight got added mid-re-roof and the flashing was improvised on site.

Failed insulated glass seal. Fog, haze, or a milky film between the panes. Water is not coming through the roof, but the unit is finished as an insulating product and it will keep sweating.

Ice damming. The Wisconsin special. Snow melts over a warm attic, refreezes at the eave, and backs water uphill against the head flashing. A perfectly good unit will leak under enough ice if the membrane around the opening is missing or too short. That is an attic ventilation and insulation problem as much as a roofing one, and it is the reason we run a fully sealed roof deck around penetrations when we tear off.

Condensation mistaken for a leak. This one saves people real money. If the drip shows up on a cold January morning with no precipitation, and the moisture sits on the glass and interior frame rather than staining the top corners of the shaft, it is condensation. The 1990s acrylic bubble domes all over Fitchburg builds are the worst offenders, along with any skylight over a bath or kitchen with weak ventilation. Sometimes the fix is a bath fan that actually vents outside instead of into the attic, not a new skylight.

If water is showing up in a ceiling and you are not certain the skylight is the source, plumbing vents, bath fan boots and pipe collars are frequent culprits. We check all of those, plus your attic ventilation, during a roof leak inspection.

What to do today, before anybody gets on the roof

Small things now protect the ceiling and make the diagnosis faster.

• Do not caulk it. Sealant smeared over flashing traps water behind it, hides where the water is actually entering, and has to be scraped off before a proper repair. It is the single most common thing we have to undo.
• Photograph the stain and date it. Snap a phone photo each time it happens. Pencil a light line at the edge of the stain so you can see whether it is growing.
• Note the weather. Drips during rain or a thaw point to flashing. Drips on a cold, dry morning point to condensation. Write down which one you have.
• Catch the water and move what is under it. Bucket, towel, furniture out of the way. If drywall is bulging with trapped water, a small relief hole over a bucket beats a collapsed ceiling.
• Turn the bath fan on and keep it running. Cutting indoor humidity helps immediately if condensation is the issue.
• Stay off the roof. Especially in winter. Nothing you can do up there beats a tarp installed by someone tied off.

Repair or replace: the honest cutoff

Repair makes sense when the unit is under roughly 10-12 years old, the glass seal is clear, and the leak traces to something specific: a nail through the flashing, a lifted shingle, dried sealant at the head, a bad gasket.

Replace when any of these are true:

• The glass is fogged, cracked, or hazy.
• The unit is acrylic and yellowed or crazed. Those domes go brittle under our UV and hail.
• It is 20+ years old on a roof that is also near the end of its life.
• The flashing kit is obsolete and no longer made for that frame profile.
• There is already rot in the decking or the shaft.

Here is the trap. Re-flashing a 22-year-old skylight can be done, and it might buy three good years, but then the seal fails and you pay for labor, flashing and a second interior repair all over again. Run the arithmetic: a repair on an old unit typically runs $500-$1,200 here, plus $1,800-$3,000 for a standalone replacement three to five years later, call it $2,300-$4,200 over the decade, against $1,200-$2,500 to replace it once, today. That is why we rarely recommend re-flashing an old unit alone.

And to be fair about the other direction: a properly installed deck-mounted glass unit, set with the manufacturer's own flashing kit on ice-and-water shield with decent pitch and sound attic ventilation, typically gives 20-25 years of dry service in this climate. Nobody can promise a hole in a roof never leaks. But sealant is a maintenance item with roughly a five-year life, and flashing is a system with a 20-year life. When a skylight leaks early, it is usually clear which one was used.

Why not buy a $300 unit at the big box and do it yourself?

Because the product is the cheap part and the risk is not. Three specific problems.

Fall risk. Anything 6/12 and steeper is genuinely dangerous, and skylights sit up in the field of the roof, not at the edge where a ladder helps. Add a vaulted interior and you also need scaffold or a tall ladder inside the room to finish the shaft.

Warranty. Manufacturers condition their installation coverage on their own flashing kit and their own instructions. A DIY install with roof cement and a bead of caulk is exactly the scenario that voids it, so if it leaks in year two, that is on you.

Your existing roof. Cutting into a shingle field that is under someone else's workmanship warranty usually ends that coverage in that area. If your roof is 6 years old and still covered, a weekend project can cost you far more than the labor you saved.

Then there is the unit itself. Builder-grade acrylic bubble domes and non-thermally-broken aluminum frames are cheap because there is no warm-edge spacer and no engineered flashing. At 15 below they sweat, the drywall stains, and we get the call in March.

Can you just remove it and shingle over the hole?

Yes, and for a lot of houses it is the right answer. Nobody in the industry likes to say it out loud because there is no unit to sell.

Rough numbers in the Madison area:

• Roof side (remove unit, sister in framing, new decking, ice-and-water shield, shingle it in): about $800-$1,800, toward the low end during a re-roof.
• Inside (insulate the cavity, close the ceiling, tape, texture, prime and paint): about $600-$2,000 depending on ceiling height and texture match.

So $1,500-$3,000 all in, often less than a solar venting replacement, and there is no penetration left to ever leak again.

Will it hurt resale? Rarely, if you pick your spot. Appraisers do not line-item skylights, and a hallway or closet unit nobody notices will not show up in a valuation. Buyers do notice daylight, though. Close the only skylights in a vaulted great room and that room reads dark on a showing, which can cost you more than the repair would have. Also worth knowing: a home inspector will flag an active leak or a fogged, stained skylight, and you have to disclose known defects to a buyer in Wisconsin. A dry closed-off ceiling beats a stained leaking one every time.

Not sure what you have up there? A free inspection settles it in about 30 minutes, and we will tell you straight if the thing can simply be repaired. No charge, no pressure, no obligation to buy a new roof. Reach out here or call the office.

Fixed vs. vented vs. solar-powered

Fixed is glass in a frame that never opens. Lowest cost, fewest moving parts, fewest leak points. Right for hallways, stairwells, and any room where you just want daylight.

Manual venting opens with a crank or a pole. Good over kitchens and baths where you want to dump humidity, which matters plenty in a Wisconsin winter. The catch is simple: if the unit sits 12 feet up a vaulted ceiling, nobody uses the pole after the first month.

Solar-powered venting has a small PV panel, a battery, a remote, and a rain sensor that closes it automatically. This is what we install most often in tall great rooms because it actually gets used, and since there is no wiring, there is no electrician. Solar units have historically qualified for a federal residential energy credit, but those rules change, so confirm with your tax preparer.

Tubular units are a different animal: small dome on the roof, reflective tube, diffuser in the ceiling. Cheap, bright, ideal for interior baths and hallways. No view, no fresh air.

Deck-mounted vs. curb-mounted

Deck-mounted units sit low on the roof deck and use an engineered step-flashing kit that weaves into the shingle courses. Lower profile, cleaner look, better long-term water performance on a shingled roof. Standard for most Madison-area homes at 4/12 pitch or steeper.

Curb-mounted units sit on a wood curb built up off the deck, usually 4 in. or taller. Required on low-slope and flat sections, and often what is already there on an older home or addition. Curbs need real counterflashing and full ice-and-water shield up all four sides. Done sloppy, they are the leakiest thing on the roof.

You generally replace like for like. Converting curb to deck mount means framing changes and a bigger bill.

Glass and heat: what matters in this climate

Low-E coated, argon-filled, dual pane is the baseline. Nothing less belongs up there. It cuts heat loss in January and solar gain in July.

Laminated glass has a plastic interlayer, like a windshield. If a limb or a hailstone hits it, it stays in one piece instead of landing on your couch. Insist on it.

Warm-edge spacers and thermally broken frames decide whether you get winter condensation on the interior frame. This is where budget units fail here.

Will a new skylight make the room hotter? Less hot than the old one. A modern Low-E laminated unit blocks a large share of the solar heat a 25-year-old clear dome let straight in. A south- or west-facing skylight in a vaulted room will still gain heat on an August afternoon, and the real answer for that is a blind. Factory blinds, including solar-powered ones on the same remote, can be added later on most quality units, so keep your model number in a drawer.

Can this be done in winter, or do you wait until spring?

Both, depending on what is happening.

Self-adhering ice-and-water shield and the sealant strips on asphalt shingles need a warm surface to bond. Most manufacturers spec roughly 40 degrees and up for self-adhered underlayment, and shingle sealant strips will not fully activate until the sun warms them. In deep cold we can still work with primer and hand-sealing, but there is also snow, ice and frost on the roof to deal with, and a frozen roof is a hazard.

So here is how we handle it in Madison and Dane County. Planned replacements get scheduled for a thaw window, and January and February thaws in Wisconsin are common enough that we do plenty of winter work. An active leak, though, does not wait for spring: we come out, tarp or install temporary flashing, set up interior water diversion so your drywall stops soaking, and put the permanent unit in when temperatures allow. Stabilize now, finish right later. That order costs you less than a rushed cold-weather install that has to be redone.

The biggest money-saver: do it during your roof replacement

If your roof is within a few years of needing replacement, wait and do both at once.

• Shared flashing work. The kit weaves into the new shingle courses anyway, and that labor is already inside the roof price.
• One mobilization. You pay for one crew, one dumpster and one cleanup instead of two.
• Membrane done right. During tear-off we run ice-and-water shield well up-slope of the opening and around all four sides. Retrofitting that under existing shingles is always a compromise.
• Decking gets inspected. Rot around an old skylight opening only shows up with the shingles off, and then it is a small line item instead of a change order.
• Clean coverage. New unit, new flashing, new field shingles, one workmanship warranty, no argument later about whose part failed.

That last point deserves plain language: once a roof is finished, most roofers, including us, will exclude or limit workmanship coverage in an area someone else cuts open. If your architectural shingles are curling and your skylight is 20 years old, they are one project, not two. See how we scope both together on an asphalt shingle roof replacement in Madison.

How long it takes, and what happens inside your house

A single-unit swap is typically a half day to one day on the roof. Two or three units, plan on two days.

You do not need to be home for the roof-side work. If there is interior shaft work we need access, and it helps to have someone there for the first 15 minutes. We put plastic sheeting on the floor and furniture below the opening and cut from above whenever possible to keep dust down, though there will still be some dust. Vaulted ceilings usually mean a ladder or small rolling scaffold in the room for a few hours, not a week of staging in your living room.

Drywall and paint are usually a second visit, because mud has to dry between coats. Our finisher typically comes back 1-3 days later. That is a different trade than the roofing crew, and we coordinate it so you are not chasing two companies.

A real example: a Verona great room last fall, two crazed 1990s acrylic domes 16 feet up over a stone fireplace. The roof crew tore off and set two solar venting units in one day, soft decking at the upslope corner got replaced, and the drywall shaft was finished on the second trip. The homeowner was at work for both.

Warranty, and how to vet whoever you hire

Warranty terms are brand-specific, so read the actual document for the model you are buying. VELUX publishes a 10-year installation warranty on its No Leak skylights, conditioned on using their flashing kit and following their instructions, with different terms for glass, product and blinds. Fakro publishes its own separate terms. Ask your contractor for the warranty PDF for the exact model on your estimate, and ask what their own workmanship warranty covers on that penetration.

Then check the basics before you sign anything:

• State credential. Wisconsin requires a Dwelling Contractor Qualifier and Dwelling Contractor Certification for permitted work on one- and two-family homes. You can look up any contractor's credential on the DSPS website.
• Insurance. Ask for a certificate of general liability and workers' compensation sent to you directly from their agent, not a photocopy from the truck.
• Manufacturer standing. We are a GAF Master Elite contractor, and we specify skylight flashing kits by part number so the manufacturer's coverage stays intact.
• Local track record. Look for a real address and real local reviews on Google, Birdeye, Angi and HomeAdvisor, not a phone number that appeared after the last hailstorm.

Ask every estimate these five questions:

1. Is the manufacturer's flashing kit included, by part number?
2. How far does ice-and-water shield extend around the opening?
3. Is decking replacement included if rot is found, and at what rate per sheet?
4. Who repairs the interior drywall, and is paint included? One trip or two?
5. What is the workmanship warranty on this specific penetration?

If one bid comes in $900 under the others, that is usually where the flashing kit went.

On paying for it, an unplanned $2,500-$4,500 lands hard. We offer financing through our lending partners, so a leaking skylight and a tired roof can be handled together on a monthly payment instead of postponed until the ceiling stains. Ask when you call and we will lay the terms out with the estimate, no application pressure.

And if the leak started after a hailstorm or a windy night, do not pay out of pocket before someone looks at the whole roof. Cracked domes and bent flashing are legitimate storm damage items, and we meet your adjuster on site to document them alongside the shingles.

Get a straight answer, free

Buckshot Exteriors has been family-owned and working on Madison and south-central Wisconsin roofs since 1979. We will come out, get on the roof, check the flashing, look at the shaft, tell you whether you have a leak or condensation, and give you written numbers for repair, replacement, and closing the opening off entirely, so you can decide with real information instead of a guess.

The inspection is free. There is no charge to find out, and nobody here is going to work you toward a new roof you do not need. If the answer is "keep an eye on it for two more years," that is what we will tell you.

Call us or request your free skylight and roof inspection today. If you have active water coming in, say so when you call. We run 24-hour emergency response and we will get it stabilized before the next storm.