Skylight Installation in Madison, WI: Cost, Leaks & Doing It Right

Skylight replacement cost in Madison: what moves the price

The spread in those numbers comes down to a short list: fixed versus venting versus solar-powered, the glass package, unit size, roof pitch and height, whether the decking around the old opening is rotted, and whether we are reusing an existing opening or cutting a new one with a drywall shaft.

Two cost items people ask about:

The 30% federal solar credit is gone for new work. The Residential Clean Energy Credit (Section 25D) covered solar-powered venting skylights and solar blinds at 30% of the unit and install cost. It was terminated for property placed in service after December 31, 2025. Practically, that means if you are buying a solar unit in 2026, budget the full price with no federal credit. If yours went in during 2025 or earlier, ask your tax preparer about claiming it for that year.

Timing. Doing skylights during a roof replacement is dramatically cheaper than doing them alone. More on that below, because it is the biggest money decision in this article.

If financing matters, we can hand you third-party lender options with the estimate. The approval, rate and term come from the lender, not from us, and we do not mark anything up for it. Ask and we will lay out what is available.

Why skylights leak in Wisconsin (it is almost never the glass)

A skylight leaks at the connection between the unit and the roof. Four failure modes cover most of what we find in Madison, Verona, Middleton, Waunakee, Sun Prairie, Fitchburg, Stoughton, Oregon, Watertown, Fort Atkinson and Baraboo:

• Sealant-only installs. Someone bedded the unit in caulk or roof cement instead of the manufacturer's step-flashing kit. Caulk is a gasket, not a flashing. Freeze-thaw cycling splits it, and it does not take many winters.
• Old curb-mounted units with site-built flashing. A wood curb framed on the deck and hand-flashed with bent metal. Fine until the metal fatigues, the corners open, or the acrylic dome shrinks away from the frame.
• Skylights left in place under a new roof. Old flashing reused or tarred over. The roof is new. The leak path is twenty years old.
• Ice damming above the head flashing. The Wisconsin one. Water backs up behind an ice dam, gets above the top (head) flashing, and runs in behind it. That is not a product defect, it is attic heat loss, weak ventilation, and whether ice-and-water shield was run properly around the opening.

That last one is why we treat a leaking skylight as an attic problem and a roof problem at the same time. If escaping heat is melting snow above the unit, you can install a brand new skylight perfectly and still see water next February.

What a correct install actually looks like

• Ice-and-water shield membrane run up the deck and lapped onto the sides and head of the opening
• The manufacturer's engineered flashing kit for that exact unit, pitch and roof covering. On a shingled Dane County roof, that means a low-profile deck-mount kit (a VELUX EDL or the Fakro equivalent), not the high-profile EDW kit meant for tile and shake
• Sill, step and head pieces installed in order and woven into the shingle courses
• Insulation and an air seal in the light shaft so warm indoor air is not hitting cold glass
• Sealant only where the manufacturer calls for it, never as the waterproofing

More on how we do it is on our skylight installation and replacement page.

Skylight repair in Madison: reflash, glass, or blind motor

Not every leaking skylight needs replacing, and we would rather tell you that up front.

Reflash only. If the unit itself is in good shape and the leak is at the flashing, we pull the surrounding shingles, replace any soft decking, run new ice-and-water shield, install a correct model-specific flashing kit, and reweave the shingles. Typically a few hundred dollars up to around $1,200 per unit depending on pitch, access and rot. That is a real repair, not a patch.

Glass seal replacement. Fogged or hazy glass means the insulated glass unit's seal failed. Some current models have replacement glass or sash assemblies available by model and serial number. Older and discontinued units usually do not, and then full replacement is the honest answer.

Blinds and motors. A dead solar blind or a control that quit is often a rechargeable battery, a control unit, or a motor, not a roof problem. Those are parts-level fixes.

Where we say don't repair: an acrylic dome that is crazed and yellowed, a rotted curb, or any unit sitting under a roof with three to five years left. Reflashing under a roof you are about to tear off means paying for the same work twice.

Not sure whether that ceiling stain is the skylight, the flashing, or an ice dam? Call us. We will come look for free, tell you what we find, and put nothing on you.

Can a handyman install it? The big-box math

We get this a lot: a $600 skylight at the home center and a handyman for a few hundred looks like a bargain against our number. Here is the part that is not on the box.

Manufacturer no-leak warranties generally require their model-specific flashing kit, installed per their printed instructions. A caulk-and-screw install typically voids that, and it can also compromise coverage on the surrounding shingle system.

When those fail, and they mostly do, we are not reflashing a skylight. We are replacing wet sheathing, sometimes rafter framing, wet insulation, and interior drywall and paint. That remediation regularly runs past what a correct install would have cost, and the drywall repair is the part nobody enjoys paying for.

Deck-mounted vs curb-mounted

Deck-mounted units sit low on the deck and use a factory flashing kit engineered for asphalt shingles. For a normal-pitch shingled home in Dane County, this is what we install. Lower profile, fewer leak points, and the flashing is a tested system instead of something bent on a tailgate.

Curb-mounted units sit on a raised wood curb. They belong on low-slope and flat roofs, some additions, and where an existing curb is genuinely sound. On a 6/12 shingle roof in Middleton, a curb-mount is usually a leftover from 1988, not a design choice.

If your unit is curb-mounted and the curb is rotted or the dome is crazed, switching to a deck-mounted unit during a re-roof is one of the best value moves in roofing.

Fixed, venting or solar powered? Glass or acrylic?

Fixed is light only. Cheapest, fewest moving parts, right for hallways and stairwells.

Manual venting cranks or pole-opens. Fine where you can reach it.

Solar-powered venting opens on a remote, closes itself on a rain sensor, and needs no wiring. Over a vaulted ceiling or stairwell, this is what most homeowners end up glad they bought, and it moves real humidity out of a bathroom.

Glass, not acrylic. Modern units use tempered outer glass with a laminated inner pane, low-E coating and argon fill. Acrylic domes are the ones we find cracked, hazed and yellowed after a decade in Wisconsin sun, and they craze or shatter first in hail. Glass also documents more cleanly for an adjuster, which is part of every storm damage restoration inspection we run in Dane County.

Heat, rain noise and resale

Glass loses more heat than insulated ceiling, but a properly specified unit is much closer to a good window than to a hole in your roof. What controls it: a low solar-heat-gain glass on south and west exposures, a laminated inner pane (also cuts sound and blocks nearly all UV), a blind on bedrooms, and an insulated, air-sealed light shaft. That shaft matters more than the glass.

Rain noise on laminated glass is real but muted, more of a soft patter than a drum. Hail is louder. Most people say they like hearing it.

On resale, daylight in a dark room shows well. A stained, fogged, 25-year-old acrylic dome does the opposite, and buyers' inspectors flag it every time.

Replace skylights with the roof, not after

A skylight's flashing is woven into the shingles. Replacing the unit later means cutting open a roof you just paid for.

During a tear-off the deck is exposed and the crew is already up there, so the swap is a modest line item. Do that same swap three years after your new roof and you pay for setup, selective shingle removal, new membrane, a new flashing kit, and blending new shingles into weathered ones. Expect several hundred to over a thousand dollars in added cost per unit, plus a patch that never looks as good.

There is also a lifespan mismatch. A 20-year-old skylight under a new asphalt shingle roof replacement has a few good years left. Your architectural shingles have 25-30.

Our rule of thumb: if the skylight is over 15 years old, the seal is fogged, the dome is acrylic, or there is staining in the shaft, replace it with the roof.

Or close the opening off entirely

Plenty of homeowners are just done with a problem skylight, and that is a legitimate choice. During a tear-off we pull the unit, frame and sheath the opening, run underlayment and shingle over it, and from the street it never existed. Roof-side cost is usually a few hundred dollars per opening. Interior drywall and paint is the variable, and some folks handle that themselves.

That "leak" might be condensation

If you see water at a skylight in January but never during a summer downpour, you may not have a leak. Warm humid indoor air rises into the shaft, hits cold glass and metal, and drips.

Telltale signs: beads or frost on the glass itself, water at the low corner of the frame, worst in bathrooms and kitchens, worst during cold snaps.

The fixes are not roofing fixes: balance attic ventilation (open intake at the soffits, exhaust at the ridge), air-seal and insulate the shaft walls, vent bath fans outside instead of into the attic, and keep winter indoor humidity reasonable.

Weak attic ventilation is also the engine behind ice dams and those head-flashing leaks. So when we inspect a skylight, we go in the attic. Skipping that is how contractors "fix" the same skylight three times. It is also why we handle the whole exterior, from residential roofing to gutters and ventilation, instead of selling you a box of glass.

Permits, Wisconsin code and scheduling reality

Permits and code. Cutting a new opening alters roof framing, which falls under Wisconsin's Uniform Dwelling Code (SPS 321) and normally means a permit, an inspection, and a properly sized header carrying the cut rafters. Swapping a unit into an existing opening generally does not. Rules differ between the City of Madison, Dane County towns, Verona, Waunakee and Fort Atkinson, so we confirm before we cut. One Madison-specific wrinkle: if your home is a designated landmark or sits in a local historic district, a street-facing roof alteration can require preservation review, and that adds weeks.

Lead times. Standard sizes are usually stock or a short order. Custom sizes, special glass and solar blinds are special-order and can add a couple of weeks, which is why we spec skylights when we sign the roof, not the week of the tear-off.

Weather during a cut-in. We do not leave an opening exposed overnight. If weather turns mid-cut-in, the opening gets decked over, membraned and made watertight before anyone leaves, and inside we tent and protect the room. Winter: unit swaps in an existing opening are fine on a dry, clear day. New cut-ins we push to spring, because shingle sealant strips will not bond cold without hand-sealing and drywall and paint want heat.

Timeline. A swap during a tear-off adds a couple of hours per unit, same day that section is open. A new cut-in is typically a day on the roof, then a day or two inside for shaft framing, drywall, tape and paint. That room is out of commission for a couple of days, not your house.

Owning one: maintenance and what actually wears out

Skylights are low maintenance, not no maintenance.

• Clear the sill flashing each fall. Leaves and pine needles pack in at the bottom edge, hold water, and back it up under the shingles. Same idea as your gutters.
• Clean the glass with plain glass cleaner or soap and water and a soft cloth. No abrasives, no razor blades on laminated glass, no pressure washer.
• Solar blind batteries are rechargeable and replaceable, and the panel keeps them topped off. Plan on servicing them at some point rather than replacing the skylight.
• Flashing life vs glass seal life. A correct deck-mount flashing system, installed with ice-and-water shield, routinely lasts as long as the shingles around it. The insulated glass seal is the shorter-lived part, and manufacturer glass warranties are typically much shorter than the flashing coverage. A fogged seal is the failure most owners eventually see, and it is a comfort and looks issue, not a leak.

Warranty and who is putting it in

Two warranties matter: the manufacturer's on the unit and its flashing system, and the contractor's on workmanship. Manufacturer terms differ by brand and model, and coverage almost always depends on their model-specific flashing kit being installed per instructions. So we hand you the actual warranty document for the unit going on your roof instead of quoting numbers from memory. Ask any bidder to do the same.

On our end, we are a GAF Master Elite roofing contractor, which means factory-trained crews and documented installs on the roof system the skylight ties into. Shop rule: we will not install a skylight without the manufacturer's flashing kit for that exact unit, pitch and roof covering. If a bidder is vague about that or plans to reuse old flashing, keep shopping.

One honest limit: in 47 years we have never seen a manufacturer or workmanship warranty pay for water driven in by an ice dam caused by attic heat loss. That is exactly why we look at the attic before we quote.

When we tell people not to add one

We would rather lose the add-on than put a hole in a roof that should not have one. We usually advise against it when:

• The slope is too low for a deck-mounted unit to shed water and snow properly
• The only good spot sits in a valley, or below a chimney or upper roof that dumps snow and ice on it
• The room already overheats on a west or south exposure and a blind will not be enough
• The attic is deep enough to need an 8-10 foot drywall shaft, which kills most of the light anyway
• The roof has three to five years left and the money belongs in the replacement

In several of those cases a rigid sun tunnel is the smarter answer. Smaller opening, flexible routing, a fraction of the cost, and a lot of daylight into a dark hallway or bath.

Have a skylight you don't trust? Let us look at it for free.

Here is what happens when you call. We set a time, walk the roof, get in the attic, and tell you plainly what is going on: flashing failure, ice dam intrusion, a blown glass seal, or plain condensation. You get photos and a straight recommendation, whether that is a reflash, one unit replaced, closing the hole off, or a full re-roof. We schedule inspections as soon as we can get a crew your way, and if you have active water coming in, say so when you call, because storm and leak emergencies get moved to the front of the line.

The inspection is free, there is no cost to find out, and nobody from our crew will lean on you to decide on the spot. We have worked these towns since 1979 and we still get most of our jobs from neighbors telling neighbors. Pressure selling is a bad way to keep that going.

One honest note on waiting: a skylight leak drips onto the top of the light shaft and travels. By the time the ceiling stains, the sheathing around the opening is often already soft, and soft decking turns a simple swap into a framing repair. Small now, expensive later.

Give us a call or reach out through our contact page and we will get someone out to take a look.