Skylight Leaking? Repair vs Replace in Michigan

A skylight is a hole cut on purpose into a system whose whole job is keeping water out, so when one starts dripping, homeowners understandably assume the worst. But water showing up around a skylight has three genuinely different causes, and they call for three different fixes at three different price points. One is not a leak at all. One is a repair job any competent roofer can knock out in a day. And one is a decision about whether the unit itself has reached the end of its life. Mixing these up is how homeowners end up paying to caulk a problem that keeps coming back, or replacing a unit that only needed its flashing redone. This guide walks the diagnosis in order, then the fix that matches each cause.

01 / THE SHORT ANSWERThree look-alikes, one decision tree

Nearly every skylight complaint we get a call about traces back to one of three sources: interior condensation forming on the glass or frame and dripping like a leak without any water actually entering the roof; a flashing failure at the perimeter, where the metal that seals the skylight curb to the shingles has pulled away, cracked, or corroded; or a failed seal or glazing on the unit itself, where the factory seal between the glass panes has broken down or a gasket around the frame has hardened and cracked. Each one has a different signature, a different fix, and a different urgency.

The rest of this guide takes each of the three causes in turn, then closes with the honest age-based question: when the unit itself is old enough that a straight reflash is a patch rather than a fix, and full replacement, especially if a reroof is already on the calendar, becomes the better spend.

02 / THE FIRST LOOK-ALIKECondensation: moisture with no roof involved at all

Condensation forms when warm, humid indoor air meets the cold surface of the skylight glass or frame, especially the metal frame edge, which conducts cold faster than the glass itself. The moisture beads up, runs down the inside of the frame, and drips onto the sill or the surrounding drywall, which looks exactly like a leak from the room below. It is most common in winter, worst right after a shower, a pot boiling on the stove, or a house that runs humid for any reason, and it tends to show up on the coldest mornings rather than during or right after rain.

The tell is timing and pattern. A condensation drip shows up on cold, dry days and gets worse with indoor humidity, not with weather outside. A true roof leak shows up during or shortly after rain or snowmelt, and it does not care how humid the house is. If the moisture appears on a clear winter morning with no precipitation in the last day or two, condensation is the leading suspect, and no amount of reflashing or caulk on the roof will fix it, because the roof was never where the water came from.

The fix for condensation lives inside the house, not on the roof: reducing indoor humidity, running bath and kitchen exhaust fans that actually vent outdoors rather than into the attic, and in some cases adding insulation around the skylight shaft where it passes through an unconditioned attic space. A skylight installed with a properly insulated light shaft and a unit rated for the local climate condenses far less than an older, single-pane or poorly shafted install. If you are not sure which of the three causes you have, a free inspection settles it, because the roof-side signs of flashing failure and the interior signs of condensation look nothing alike once someone is actually looking at both.

03 / THE SECOND LOOK-ALIKEFlashing failure at the perimeter

If the drip does track with rain or snowmelt, the next and most common suspect is the flashing, the formed metal that wraps the skylight curb and weaves into the surrounding shingles the same way chimney flashing does. A skylight flashing kit has several parts working together: head flashing above the unit, step flashing woven into the shingle courses along the sides, and a sill piece below, usually paired with a membrane or apron underneath for backup. When any one of these pieces pulls loose, corrodes, or was installed with gaps in the first place, water finds its way past the shingles and down into the roof deck around the curb.

Flashing failure tends to announce itself gradually: a stain that grows slowly on the ceiling or the drywall around the skylight shaft, worse after heavy rain or a hard freeze-thaw cycle, and often concentrated at one corner or side rather than evenly around the whole opening. That asymmetry is a useful clue, since a true leak usually enters at one specific failed joint, not uniformly around the frame the way a condensation drip does.

The fix, when the skylight unit itself is sound, is straightforward: reflashing with a proper manufacturer flashing kit matched to the unit and the roofing material, rather than a generic bent-metal patch or a bead of roofing cement smeared over the old flashing. A correctly reflashed skylight should hold for as long as the surrounding roof does. Reflashing without replacing the unit falls within our general roof repair range of $350 to $3,200, with the exact price depending on how much of the surrounding shingle field has to come up to do the flashing correctly and whether the deck underneath needs any attention.

What a proper reflash actually replaces

A homeowner comparing quotes benefits from knowing what should be on the invoice. A real flashing repair pulls back the shingle courses around the curb, removes the old flashing pieces entirely rather than working around them, and sets a new kit piece by piece: head flashing first, then step flashing woven course by course up each side so every shingle overlaps the piece below it, then the sill piece last so it sheds onto the roof rather than behind it. An ice and water membrane at the curb underneath the metal is standard practice in a Michigan climate, since it is the backup layer if anything above it ever fails again.

• Old flashing pieces removed, not caulked over or bent back into place
• New head, step, and sill flashing matched to the roofing material
• Shingle courses re-woven around the curb, not just laid back down loose
• A membrane layer at the curb as backup waterproofing beneath the metal
• Photos of the deck condition under the old flashing before it closes back up

That last item matters more than it sounds. Pulling the flashing is the one moment anyone can actually see the deck condition around the curb, and a contractor who does not document it is asking you to trust that nothing underneath needed attention.

04 / THE THIRD LOOK-ALIKEA failed seal or glazing on the unit itself

The third cause lives in the skylight unit rather than the roof around it. Modern skylights are insulated glass units, two or three panes sealed together at the edge with a spacer and a factory seal, similar to a double-pane window. When that edge seal fails, moisture gets between the panes and shows up as fogging, a milky haze, or visible condensation trapped inside the glass itself, rather than dripping. That is a glazing failure, not a leak, and no amount of roof work fixes it, because the problem is sealed inside glass that flashing and caulk cannot reach.

A related but separate issue is the perimeter gasket, the rubber seal between the glass unit and the frame, or between the frame and the curb on an older unit. Gaskets harden and crack with UV exposure and years of temperature swings, and a cracked gasket can let water past the frame even when the roof-side flashing is perfectly intact. This shows up as a leak that tracks with wind-driven rain specifically, since a straight-down rain may not find the gap the way angled, wind-driven rain does.

Fogged glass from a failed seal is a manufacturer defect issue as much as a roofing one, and it is worth checking whether the unit is still inside a manufacturer glass or seal warranty before paying out of pocket for anything. A cracked perimeter gasket on an otherwise sound frame can sometimes be replaced on its own, but on many units the gasket is not sold as a separate part, and a full unit swap is the practical fix. Either way, this cause points toward the unit, not the roof around it, which is the opposite of the flashing scenario above.

It is worth saying plainly that these three causes are not always neatly separate. An older unit can have a slightly failed seal and a tired flashing job at the same time, and the honest diagnosis is whichever combination actually applies to your roof, not whichever single cause is easiest to explain. That is exactly why a from-the-attic and on-the-roof look, rather than a guess from the ceiling stain alone, is the only way to be sure.

A roofer who blames the skylight without checking the flashing, and a roofer who reflashes without checking the glass, are both guessing at half the problem.

05 / THE AGE QUESTIONWhen reflashing is a patch, and replacement is the honest call

None of the three causes above answer the question every homeowner eventually asks: should I fix what is there, or just replace the whole unit? The honest answer depends less on which of the three problems you have and more on how old the skylight is and what shape the roof around it is in.

A newer skylight with a flashing failure is usually a clear repair call. Reflash it properly, and a sound unit keeps performing for years. An older unit, particularly one original to a roof that is itself nearing the end of its rated life, is a different conversation. Glazing seals, gaskets, and even the frame finish age on their own timeline, and a unit old enough to be showing a failed seal today is often close behind on a flashing or hardware failure tomorrow. At that point, paying to reflash a unit that will need attention again in a few years is spending real money to delay a decision rather than settle it.

SITUATION	LIKELY CALL	TIMING
Flashing failure, unit otherwise newer and sound	Reflash with a manufacturer kit	Standalone repair, any time
Failed seal or gasket on a unit near end of life	Replace the unit	Standalone, or bundle with other roof work
Any skylight issue and the surrounding roof is due for replacement soon	Replace the unit during the reroof	Bundled with the reroof, not before

That last row is the one worth planning around. If the roof itself is within a few years of needing replacement anyway, reflashing an old skylight now and reroofing around it later means paying for flashing labor twice, once for the standalone repair and again when the reroof crew has to open the same curb back up. Our guide on replacing skylights during a reroof covers that overlap in detail: the flashing has to come apart for the reroof regardless, so a new unit gets fresh manufacturer flashing matched to the new shingles and a warranty that is not split between an old skylight and a new roof.

Skylight unit replacement cost is not part of our published price canon on this page, since it depends on the unit size, glazing tier, and whether it is happening alongside a reroof, and we would rather give you an honest number after looking at the actual unit than an invented figure here. What we can say with the same confidence as the rest of this site: standalone flashing repair on a sound unit falls within our general roof repair range of $350 to $3,200, and if the roof itself is heading toward a full replacement, that project follows the same published ranges as any other reroof, with the skylight folded into the same scope rather than priced separately.

None of this has to be guesswork on your end. A free inspection looks at the flashing, the unit, and the roof around it together, and tells you plainly which of the three causes applies and which column of the table above your house falls into.

06 / GETTING A REAL ANSWERFree inspection, straight answer, no upsell

We would rather tell you the fix is a $350 reflash than talk you into a unit you do not need, and we would rather tell you honestly that an aging unit is worth replacing than have you pay to patch the same failure twice. Our inspection covers the skylight flashing, the frame and glazing, and the attic side of the shaft, with photos of everything we find, and it costs $0 with no obligation. If a reroof is in your near future anyway, ask us to look at both at once; our published pricing covers the full range of jobs from a single reflash to a full replacement, and the cost calculator gives you a ballpark on the roof side before anyone visits.

If your skylight symptoms point toward the roof needing attention beyond just the one unit, our roof replacement page walks the full process and pricing, and the instant estimator runs the same published ranges against your own roof in about 60 seconds. Either way, the skylight itself gets the honest look it deserves before anyone quotes you a fix.