Skylight Leaking? It's Almost Always the Flashing.
Water dripping around your skylight isn’t a sign the skylight itself is broken. In the vast majority of cases, it means the metal flashing that seals the skylight to the surrounding roof system has failed, and what looks like a skylight problem is actually a roofing problem. Here’s what’s happening and what it takes to fix it properly.
Signs Your Skylight Is Leaking or About to
Skylight leaks show up in different ways depending on where the failure is. Some are obvious, others are easy to attribute to the wrong cause.
Water Dripping During or After Rain
Active dripping around the skylight frame, down the interior shaft, or onto the ceiling during a rainstorm is the clearest sign. The drip often doesn't start until the rain is heavy or has been falling for a while, because the failed flashing may shed light rain but fail under volume or wind- driven conditions.
Brown Staining on the Ceiling Around the Frame
Yellowish-brown water staining on the drywall or plaster ceiling immediately surrounding the skylight frame is often a sign of a slow, chronic leak rather than an acute one. The staining may be months or years old by the time you notice it, meaning water has been moving through the system for some time.
Leaking During Chinooks or Spring Snowmelt
A skylight that leaks specifically when snow is melting rapidly (during a Chinook or warm spring day) but not during rain is a strong indicator of an ice dam forming at the skylight perimeter. Meltwater is pooling against the skylight curb and being forced under the flashing by the dam.
Condensation Inside the Skylight Glass
Condensation forming between the panes of a double or triple- glazed skylight means the seal between the glass layers has failed and warm moist air is reaching the cold inner surface. This isn't a flashing problem, it's a glazing unit failure, and it means the unit itself needs to be replaced, not just the flashing around it.
Soft or Bubbling Drywall in the Skylight Shaft
If the interior drywall lining the skylight shaft (the angled tunnel from the roof to the ceiling) is soft, bubbling, or showing mould, water has been running down inside the shaft for long enough to saturate the framing. This indicates a chronic leak rather than a recent one.
Cracked or Dried Sealant Visible Around the Frame
If you can safely see the skylight from the roofline, visible cracking or shrinkage in the sealant around the frame perimeter is an early warning. UV exposure and Alberta's freeze-thaw cycles degrade sealant quickly, and once it cracks and pulls away from the frame, water has a direct entry path.
Why Skylights Leak — and Why Caulk Won't Fix It
A skylight is a penetration through your roof system. Like a chimney, a plumbing vent, or a dormer wall, it creates an intersection between a vertical surface (the skylight curb or frame) and a sloped roof plane. That intersection is sealed by a system of metal flashing components, and it’s these components that almost always fail first.
The flashing around a skylight has two main parts: the step flashing (small L-shaped metal pieces that integrate with the shingles along the sides of the skylight) and the saddle or counter flashing at the upper edge, which directs water around the top of the frame and prevents it from collecting behind the skylight. When either of these fails, usually through sealant breakdown, metal corrosion, or thermal movement that pulls the flashing away from the frame, water enters.
In Alberta’s climate, the freeze-thaw cycle is particularly destructive to skylight flashing. Water that works its way behind a slightly compromised flashing seam freezes, expands, and forces the gap wider. After 40 or more freeze-thaw cycles in a single winter, a flashing that was marginal in autumn is fully failed by spring. That’s why so many skylight leaks in Calgary show up in March and April, not during the summer rain season.
WHY CAULK IS NEVER THE REAL FIX
Applying caulk or roofing tar over failed skylight flashing is the most common temporary patch, and it almost always fails within one or two seasons. Sealants applied over failed metal flashing don't bond properly to aged or corroded surfaces, and they can't bridge the thermal movement that caused the original failure. The proper fix is removing the surrounding shingles, replacing the flashing components correctly, and re- integrating them with new shingles. It's more involved, but it's what actually works.
What a Skylight Leak Costs You When It's Left
A skylight leak that seems minor on the surface is often doing significant damage in places you can’t see. Here’s what’s happening inside the roof system and the ceiling structure while you’re delaying the repair.
Shaft Framing Rot and Mould
The skylight shaft (the framed tunnel from the roof opening to the ceiling) is typically framed with dimensional lumber and lined with drywall. Chronic water intrusion from a failed flashing saturates the framing over time, causing rot and providing the moisture conditions for mould to establish. By the time mould is visible on the interior drywall, it’s already in the framing behind it.
Insurance Claim Complications
If a skylight leak is caused by a sudden and accidental event (a hailstorm cracking the glazing, a storm damaging the flashing), it may qualify as an insured loss. But if an adjuster determines the leak is from gradual deterioration of sealant and flashing that went unaddressed over years, the claim will likely be denied as maintenance-related. Documentation of when the leak started matters.
Escalating Repair Scope
A flashing repair handled early (before water reaches the framing) typically costs $500 to $1,500. The same repair after 2 to 3 years of chronic water intrusion, once framing replacement and mould remediation are added to the scope, can run $3,000 to $8,000 or more depending on the extent of the damage. The flashing repair cost doesn’t change. It’s everything else that escalates.
What to Do Right Now
If your skylight is actively leaking, here's how to manage the situation safely while you arrange a proper inspection and repair.
ON "REPLACING JUST THE SKYLIGHT"
Many homeowners assume that if the skylight is leaking, the entire unit needs to be replaced. In most cases that's not true. The glazing unit itself (the glass or acrylic dome) rarely fails in a way that causes leaking. The flashing around the unit is what fails, and in the majority of cases, a proper flashing rebuild with new step flashing, counter flashing, and ice-and-water shield at the perimeter is all that's needed to stop the leak for good, without touching the skylight unit itself.
How We Diagnose and Repair Skylight Leaks
We don't apply sealant and hope for the best. Our approach starts with understanding exactly where the water is entering the system before any repair work begins.
Roof-Level Inspection of All Flashing Components
We inspect the step flashing along both sides of the skylight, the saddle or counter flashing at the head (upper edge), the apron flashing at the foot (lower edge), and all sealant lines at the frame perimeter. We also check the condition of the shingles immediately surrounding the unit for signs of hail impact, since a hailstorm that cracked the glazing may have also compromised the soft metal flashing components.
Interior Assessment of the Shaft
We assess the interior of the skylight shaft for signs of framing moisture, mould, or structural softness. If the framing has been compromised by chronic water intrusion, a surface flashing repair won't solve the problem long-term. We identify the full scope upfront so you're not surprised partway through the job.
Proper Flashing Rebuild — Not a Patch
flashing, install new step flashing integrated correctly with each shingle course, install new counter flashing at the head, and apply ice-and- water shield at the perimeter before reinstalling shingles. This is how a skylight flashing is supposed to be done, and it's what's required for a repair that will hold through Alberta winters.
Full Unit Replacement When Needed
If the skylight glazing unit has failed (cracked acrylic, fogged double- pane glass, or a frame that's warped beyond sealing), we can coordinate full unit replacement. We work with standard skylight sizes from major manufacturers and can source replacements that fit existing curb dimensions wherever possible, minimizing the framing work involved.
DAVID R. , Tuscany, NW Calgary
Our roof was 17 years old and we'd been quoted $18,000 for a replacement. Advanced Level Roofing assessed it and said the decking was sound and the shingles had good life left — they recommended the life extension treatment instead. We paid a fraction of the replacement quote, and two years later the roof is performing exactly as they said it would. They could have sold us a replacement and they chose not to — that kind of honesty is rare.
Yannick Rouette , Calgary
Advanced Level Roofing replaced the roof on my house in April 2025. The previous roof was damaged by hail and I paid for Class 4 hail-resistant shingles. They delivered the shingles on a Thursday and came for the removal and installation on Saturday. They did all the work in a single day, from 8 am to 4:30 pm. The employees were nice and careful. They cleaned everything around the house and passed their rolling magnet over my yard ten times to remove all nails. They sent me a photo inspection of the roof. I would recommend this company. Their prices are great.
JOHN D. , Calgary
Yesterday I had my roof replaced by a team from Advanced Level Roofing. True professionals who know what they do. I saw them working on houses around me for two years now and their jobs look awesome. You can see other companies dragging a roof job on for days, but these guys try their best to do it in one day and that was the case for me. The whole process from estimate to installation was a breeze. The price was fair and the estimator answered all my questions. When dusk set in, they were gone and everything was clean and nice around the house. The roof looks awesome. As much as I like what you've done, I don't want to see you again for the next 20 years or so!
What Does Skylight Leak Repair Cost, and Does Insurance Apply?
The cost of a skylight leak repair depends on what’s actually failing. A flashing rebuild (the most common repair) typically runs between $500 and $1,500 for a single skylight, depending on the size of the unit, roof pitch, and extent of surrounding shingle work required. If the surrounding shingles also need to be replaced because of age or hail damage, that adds to the scope.
Full skylight unit replacement (when the glazing or frame itself has failed) runs from $1,500 to $4,500 or more depending on the unit size, glazing type, and whether the curb framing needs to be rebuilt. Custom or non-standard size skylights carry a higher material cost.
On insurance: if your skylight was damaged by a covered event (hail cracking the glazing, wind tearing the flashing, or a falling tree), a claim is likely appropriate and we can assist with documentation and adjuster representation. If the flashing has failed gradually through age, UV degradation, or freeze-thaw cycling, most Alberta policies will classify this as a maintenance issue rather than a covered loss. We’ll give you an honest assessment of which situation you’re in during the inspection.
Dealing With a Related Problem?
Skylight leaks are often part of a broader picture. These guides cover the problems most commonly connected to what you're seeing.
Emergency Roof Repair
If the skylight is actively dripping into your home during a storm and the situation needs immediate attention, this guide covers what to do in the next 30 minutes.
Ice Dam Removal and Prevention
If your skylight leaks specifically during Chinooks or spring snowmelt but not rain, ice damming at the skylight perimeter is almost certainly the cause. This guide covers the full system fix.
Hail Damage Roof Repair
Hail can crack acrylic skylights, dent metal flashing, and compromise the surrounding shingles simultaneously. If damage followed a storm, this guide covers what to look for.
Skylight Repairs Across Calgary and Western Canada
We carry out skylight flashing repairs and full unit replacements across all our markets. Given how aggressively Alberta's freeze-thaw cycles attack skylight flashing, this is one of the most common repair calls we get in Calgary and Edmonton each spring.
Frequently Asked Questions
Is it the skylight that’s leaking, or the roof around it?
Can I fix a skylight leak myself?
My skylight only leaks when it snows, not when it rains. Why?
How long does a skylight flashing repair take?
My skylight is foggy between the panes. Is that related to the leak?
Should I replace my skylight if I’m already getting a new roof?
