Skylights · Calgary
Skylight repair and replacement in Calgary
I'm Stivi of Stivi Roofing, and I repair and replace leaking skylights in Calgary on shingle roofs and flat roofs. When the glass and frame are sound, I re-flash the skylight with new membrane and flashing around the curb. When the unit is fogged or cracked, or the curb is rotten, I remove it, build a new wood curb and install a new skylight in the same opening.
- Shingle roofs and flat roofs
- New curbs built from solid wood
- Flashing lapped, not caulked
Problem 1
Why is my skylight leaking in heavy rain?
A skylight leaks in heavy rain because the flashing around its curb no longer sheds water. The curb is the raised frame the skylight sits on, and its flashing is the metal and membrane that seal it to the roof. When that flashing lifts, rusts or was never lapped properly, hard rain runs straight behind it.
Skylights on the low side of a roof get the most water, because everything above them drains down onto the curb. Caulking around the frame more than once is a sign of exactly this: each new bead slows the drip for a season and then fails again.
Problem 2
Why does my skylight drip in winter when it isn't raining?
A skylight that drips in winter without rain has one of two problems: condensation or ice. Warm, moist air from the house condenses on cold glass and the shaft walls, then runs down like a leak. Or snow melts above the skylight during a chinook, refreezes at the cold curb, and backs water up under the flashing.
The two need opposite fixes, so telling them apart matters. Condensation is an indoor humidity and insulation problem. Ice backing up is a roofing problem.
Problem 3
What happens when a skylight curb rots?
When a skylight curb rots, the skylight loses its solid base. Fasteners pull out, the frame shifts, and the flashing tears away from it. Every rain then soaks the wood further and stains the drywall in the shaft below.
Curbs rot from slow leaks that went on for years before anyone saw a drip. By the time the shaft drywall is stained, the wood behind the flashing has usually been wet for a long time.
What I've learned
Sealant is not a skylight repair
Sealant on a skylight buys time, nothing more. A skylight stays dry because its flashing and membrane are lapped like shingles: each layer runs under the one above it, so water always flows over a joint and never into it. That works without a drop of caulking.
So when I repair a skylight, I take the flashing apart and rebuild those laps. If the curb or the unit is failing, I replace them rather than seal over them. That's why the repair lasts as long as the roof around it.
Fix 1
How I re-flash a leaking skylight
I re-flash a leaking skylight by removing the roofing and old flashing around the curb, then rebuilding from the bottom up. Self-adhered membrane wraps the curb and runs out onto the deck. On a shingle roof, new step and head flashing go in with the shingles woven over them. On a flat roof, SBS base and cap sheet run up the curb sides and lap onto the roof.
The water above the skylight gets directed around it, and nothing depends on caulking.
Fix 2
How I tell skylight condensation from a skylight leak
I tell condensation from a leak by where and when the water appears. Condensation forms evenly on the glass and shaft on cold mornings, drips from the lowest edge of the frame, and stops when the glass warms. A leak stains one side of the shaft, follows rain or a chinook melt, and shows wet wood at the curb from the roof side.
If it's a leak, I re-flash or replace. If it's condensation, I tell you so, and the fix is lower indoor humidity or a better-insulated unit, not roofing work.
Fix 3
How I replace a skylight and its curb
I replace a skylight by removing the old unit and cutting out the rotten curb down to solid framing. I build a new curb from solid lumber, wrap it in self-adhered membrane that laps onto the deck, and set the new skylight on it. Then I install new flashing and weave the shingles or membrane back into the roof.
On a flat roof replacement, I set the new skylight curbs into the coverboard before the membrane goes on, so each one is flashed into both plies.
Next step
Repair or replace your skylight? You'll know after one visit
Stivi Roofing repairs and replaces leaking skylights in Calgary. A sound skylight gets new membrane and lapped flashing around its curb. A fogged, cracked or rotted one gets a new curb and a new unit in the same opening, on a shingle roof or a flat roof.
Send me a photo of the skylight from inside and, if you can, from the roof. If the leak turns out to be somewhere else on the roof, my roof repair page explains how I trace it.
Skylight questions Calgary homeowners ask me
- Who do I call to fix a leaking skylight?
- Call a roofer. A skylight leak almost always comes from the flashing and membrane around the curb, which is roofing work. A glass company replaces broken or fogged glass, but it does not open up the roof around the skylight.
- Can I replace a skylight without replacing the roof?
- Yes. I remove the shingles or membrane only around the skylight, take out the old unit, rebuild the curb if needed, and weave new membrane, flashing and roofing back into the existing roof. The rest of the roof stays as it is.
- Can a leaking skylight be repaired?
- Yes, when the glass is clear, the frame is sound and the curb is solid wood. Then the repair is new flashing and membrane around the curb. A skylight with fog between the panes, cracked glass or a rotten curb needs replacing instead.
- Do skylights need to be resealed?
- A properly flashed skylight does not depend on sealant to keep water out, so it does not need regular resealing. If yours needs fresh caulking every year or two to stop a drip, the flashing underneath has failed and needs to be rebuilt.
- How do I know when a skylight needs replacing?
- Replace a skylight when you see fog or moisture between the panes, cracks in the glass or dome, or soft, stained wood in the curb or the shaft below it. Each of these means the unit or its frame has failed, and new flashing alone will not fix it.