A skylight is a hole in your roof. A good one is a beautifully engineered hole with a sound waterproofing system around it — but it’s still the single most vulnerable penetration on most Michigan roofs, along with the chimney.
When one starts dripping, the instinct is to blame the glass. That’s almost never the problem.
Here’s what actually goes wrong with skylights in Dearborn and the Detroit Metro area, and how to tell repair from replacement.
First: Is It a Leak, or Is It Condensation?
This matters, because the fixes are completely different and a lot of “leaking” skylights aren’t leaking.
Condensation shows up as water on the interior glass or running down the inside of the shaft, typically in cold weather, worst on the coldest days, and often worse in kitchens and bathrooms. It’s warm, humid indoor air hitting a cold surface. The skylight is fine. The problem is humidity and attic ventilation.
An actual leak shows up during or right after rain or snowmelt, usually as staining on the drywall of the light shaft or on the ceiling around the opening, and often runs on a schedule that matches the weather rather than the temperature.
If your “leak” appears on cold clear days and not during rain, chase the ventilation and indoor humidity before you touch the roof. Our post on attic ventilation and insulation covers the underlying issue.
What Actually Fails on a Leaking Skylight
Working from most to least common:
1. Failed flashing. The step and head flashing that ties the skylight into the surrounding shingles is the primary waterproofing. When it corrodes, lifts, gets damaged during another roofing job, or was never installed correctly to begin with, water gets in around the unit. This is the number one cause we find.
2. Sealant relied on as waterproofing. Caulk is a maintenance detail, not a flashing system. A skylight that has been sealed and re-sealed with tubes of caulk is a skylight whose flashing failed years ago. Once that sealant cracks — and Michigan’s freeze-thaw cycle guarantees it will — water goes straight in.
3. Ice dams. This is the distinctly Michigan failure. Meltwater backs up behind an ice dam, gets under the shingles above the skylight, and comes in over the head flashing. The skylight isn’t defective; the roof above it is holding water where it was never designed to sit. Ice and water shield around the opening and proper attic ventilation are the real fix.
4. Failed glass seal. On insulated glass units, a failed edge seal lets moisture between the panes. The sign is permanent fogging or haze inside the glass that you can’t wipe off. This can’t be repaired — the unit gets replaced.
5. Rotted or damaged curb and frame. On older units, especially site-built curbs, long-term water intrusion rots the framing the skylight sits on. That has to be rebuilt before any new unit goes in.
6. Old acrylic bubble skylights. These are common on Detroit-area homes built in the 1960s and 1970s. Acrylic yellows, gets brittle under UV, and eventually cracks. There’s no repair path for a crazed acrylic dome.
Repair or Replace?
Repair is the right call when the unit is relatively young and sound, the glass is clear with no internal fogging, the frame and curb are solid, and the problem traces to flashing or sealant. A proper flashing kit installed correctly will hold for years.
Replacement is the better investment when the glass seal has failed, the frame or curb is rotted, the unit is an old acrylic dome, the skylight is past roughly twenty years, or — importantly — you’re replacing the roof anyway.
That last one is worth emphasizing. During a roof replacement, the skylight flashing comes off and goes back on regardless, so most of the labor cost of replacement is already being spent. Putting a fifteen-year-old skylight back under a brand new roof means cutting that new roof open again in a few years, at full cost.
Why Roofers, Not Handymen, Should Do This Work
Skylight repair is roofing work. The flashing integrates with the shingle courses, the underlayment, and the ice and water shield around the opening. Doing it correctly means working within the roofing system, not caulking around the outside of it.
The fastest way to turn a small skylight problem into a large one is a repair that seals the surface while water continues to travel underneath. We see plenty of skylights where four or five layers of caulk are hiding the fact that the flashing has been gone for a decade — and the decking underneath has been quietly rotting the whole time.
What We Do
NorthWest Construction is an authorized VELUX installer, and we handle skylight work as part of the roofing system it belongs to:
- Leak diagnosis, including telling you honestly when the problem is condensation rather than a leak
- Flashing replacement with the correct manufacturer flashing kit for your roof type
- Ice and water shield around the opening to address ice dam intrusion
- Full skylight replacement, including VELUX fixed, venting, and Sun Tunnel units
- Curb and decking repair where water has already done damage
- Light shaft and drywall repair after the roof side is sound
- Attic ventilation assessment, since it’s frequently the underlying cause
You can see completed work in our skylights gallery, or read more about VELUX skylights and sun tunnels.
Don’t Wait on a Skylight Leak
Water coming in around a skylight is running across roof decking and framing before it ever reaches your ceiling. By the time there’s a stain on the drywall, the damage above it has been developing for a while — and in Michigan, a leak left through a winter of freeze-thaw gets worse fast.
We inspect skylights throughout Dearborn, Dearborn Heights, Allen Park, Livonia, Taylor, Westland, Redford, and the surrounding Detroit Metro communities.
Call (313) 277-7676 or contact us online for a free skylight and roof inspection.