Why Flashing Is Where Most Skylights Fail
Nine times out of ten, a skylight stain at the curb is a flashing problem. Flashing is the layered metal system that sheds water around the skylight: an apron at the bottom, step flashing up the sides woven into the shingles, a head flashing at the top, and underneath it all, ice and water shield sealed to the curb.
When any one of those layers is missing, rusted, reversed or replaced with caulk, water gets in. We see every version of it. Flashing repair means stripping back to the deck and rebuilding the layers in the right order.
The 5 Flashing Failures We Fix Most Often
- Missing head flashing, so water from above runs straight under the top of the unit.
- Rusted step flashing on 25+ year-old skylights.
- Caulk instead of flashing, especially on brick-abutting skylights.
- No ice and water shield under the flashing.
- Reused flashing after a re-roof.
Residential Flashing Repair
Asphalt Shingle Roofs
The most common roof in the GTA. Velux EDL kits or step flashing. We pair the kit with full ice-and-water shield around the curb, lapped shingle-style, so a $185 EDL reinstall outlasts a $300 caulk-and-go patch within a single freeze-thaw cycle.
Metal Roofs
Velux EDW kits and custom-bent trim for standing seam. Standing seam and ribbed panels can take a few extra hours because the flashing tucks under the seam clips. EDW kits are commonly $120 a meter. We hand-form for the corners.
Tile and Slate Roofs
Hand-formed flashing, often copper on heritage homes. Copper runs hand-formed in the truck and on the roof to match the slate profile. Copper is much heavier than aluminum but lasts more than 50 years.
Skylights Against Brick Walls
Reglet counter-flashing cut into mortar joints. We cut a reglet groove into the mortar and tuck the counter-flashing into it, then seal. Surface-mounted strips caulked to brick fail within a few seasons.
Low-Slope Roofs
Curb-mount details and extended membrane underlayment. Curb-mount units need extended membrane up the curb at least 4 inches. Membrane is torched or cold-applied over the existing roof.
Skylights Near Valleys
Crickets and extended flashing so valley water is diverted. Crickets divert snow and water around the unit. The cricket itself is often $200 to $400 in sheet metal.
Chimneys Next to Skylights
Shared counter-flashing details done properly. Shared counter-flashing is detailed to lap correctly around both elements. Brick reglet cutting is often the same crew doing both.
Commercial Flashing Repair
Curb-Mount Units on Membrane Roofs
Membrane re-tie and new metal cap flashing. Curb-mounts on flat membrane need the cap flashing pulled, membrane re-tied to the curb, and cap reinstalled. Often staged around rain windows.
Retail Domes
Resealing and new cap flashing between replacement cycles. Resealing and new cap flashing keeps domes alive between full replacement cycles. Cap flashing runs from $300 to $600.
Mixed-Use Buildings
Brick parapet skylights with reglet details. Brick parapet skylights need reglet counter-flashing at the parapet tie-in. We coordinate with other trades for safe roof access.
Warehouses
Aluminum cap flashing over raised curbs. Aluminum cap flashing over raised curbs is standard 0.032 aluminum brake-formed. The unit price drops with quantity.
Specialty Flashing Work
Copper Flashing
For slate and heritage roofs. Copper flashing is hand-formed on the roof to match the slate course. Copper is heavy and expensive, $40-70 a foot, but it lasts the life of the roof.
Brick Reglet Counter-Flashing
For party walls and chimneys. We cut a reglet into the mortar, never the brick face, and tuck the counter-flashing inside. Sealed with masonry caulk, not silicone.
Cricket Flashing
Above wide skylights to divert snow. Crickets are 4 to 8 inches tall depending on the skylight width. Sheet metal bent to match the roof pitch and lapped under the shingles above.
Factory Kit Upgrades
Replacing improvised flashing with a pre-engineered kit. We swap improvised flashing for a Velux EDL, EDM or EDW kit matched to the unit and roof. EDL kits from $185, EDW up to $385.
Flashing Materials
| Roof type | Flashing system |
|---|---|
| Asphalt shingle | Velux EDL kit or aluminum step flashing |
| Tile / profiled | Velux EDW kit |
| Low profile | Velux EDM kit |
| Slate / heritage | Hand-formed copper |
| Brick-abutting | Reglet counter-flashing |
| Membrane | Aluminum cap flashing over membrane tie-in |
All over Grace Ice & Water Shield, with Grace Vycor at corners.
Our Flashing Expertise
We photograph every flashing layer before it is covered, so you can see the work, not just trust it. Twenty years of re-flashing other people’s skylights taught us exactly where shortcuts happen.
What Actually Stops Homeowners From Re-Flashing
“Can’t you just seal the gap?”
In our opinion, sealant on flashing is a bandage. It cracks within a couple of Toronto winters and hides the real problem. A proper re-flash strips back to the deck and rebuilds the layers in order, $400 to $1,200.
“I’d rather replace the whole skylight.”
If the unit is sound, re-flashing costs a fraction and lasts as long. A full replacement runs $1,400 to $3,800 installed, so re-flashing makes sense when the glass and frame are still good.
“The roofer said it’s fine.”
If it stains after rain, it is not fine. We test it with a hose on the curb before quoting. If the stain is gone after a dry spell, the leak is almost always flashing, not glass.
“It’s a weird roof.”
Brick walls, slate, metal. We hand-form for anything a kit does not fit. Hand-formed copper and reglet counter-flashing are routine work for us.
Flashing Repair Timeline
Inspection
Same-day or next-day visit. We check the curb, lift a few shingles and test for soft wood before quoting. Photographs of every layer go in the quote packet.
Quote
Kit or hand-formed, itemized. Itemized quote with kit cost, labour, ice and water shield and any curb repair as separate lines. Permit is not a line because flashing repair does not need one.
Repair
Two to five hours. Old flashing stripped, ice and water shield replaced, new flashing lapped in the right order. Most GTA asphalt shingle flashing repairs are done before lunch.
Test
Hose test and photos. We hose-test the curb before leaving the roof and re-check the interior after the next rain. Photos of every covered layer get emailed that night.
Skylight Flashing Repair Cost in Toronto: What You Are Paying For
Removal of Old Flashing
Careful work around shingles. We lift, not tear, the surrounding shingles so the re-roof bill stays where it belongs. Stripped flashing goes to the metal recycler.
Ice and Water Shield
Never skipped. Grace Ice & Water Shield, two layers around the curb. Vycor at the corners. OBC 9.26 good practice and the only way flashing lasts in a Toronto winter.
Flashing Kit or Metal
$185 to $385 for kits, more for copper. Velux EDL is $185, EDW is closer to $300, EDM is about $260. Copper runs $40-70 per foot hand-formed on the roof.
Labour
Mostly roof time. Labour is mostly roof time: strip, prep, install, lap, test. Two-person crew, half-day to full day depending on access.
Brick Work
Reglet cutting and sealing. Reglet cutting with a diamond blade, never hammer-and-chisel. Tuck-pointed after the counter-flashing is set. Reglet jobs add $400 to $600 to the line.
Curb Repair
Only if rot is found. Curb rot gets quoted as a separate line so the homeowner can see it before any wood is cut. Curb repair typically adds $200 to $500.
Flashing Repair vs Leak Repair vs Replacement: Which Service You Need
Known flashing failure: this page. Unknown source: start with leak repair diagnostics. Old fogged unit with bad flashing: replacement.
Fixed, Venting or Solar: Choosing Your Skylight Type
Flashing repair keeps your current unit. If you are replacing anyway, consider upgrading to venting or solar.
Flashing Repair Timeline in Toronto: What to Expect Week-by-Week
Most flashing repairs are inspected and completed within the same week.
Why Homeowners Trust Our Flashing Work
Every layer photographed, every joint lapped the right way. We specd it the way the manufacturer intended. We have been rebuilding failed flashing across Toronto and the GTA for over twenty years, certified for both Velux and Fakro since 2004 with in-house WSIB-covered crews and no subcontractors on the roof. Every quote is itemized with the kit, labour, ice and water shield and any curb repair on separate lines, every curb gets Grace Ice & Water Shield and Vycor to OBC 9.26, and every covered layer gets photographed so you can see what you paid for. Trust our repair is warranty in writing, with a leak-free flashing warranty on most residential skylights.
