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Chimneys, Flashing & Vents

Chimney Flashing Repair in Toronto & the GTA

If your house has a leak near the chimney, the odds heavily favour the flashing, not the chimney itself — and not the roof around it either. A chimney punches a hole through the roof, and the two-part metal system sealing that hole is the most failure-prone detail on most GTA roofs: step flashing laced into the shingles, and counter flashing cut into the mortar joints overtop. When either layer rusts, loosens or pulls out of the masonry, water tracks down the brick into the house.

The right repair depends on which layer failed. Counter flashing that's worked loose from its mortar cut can be re-secured and resealed. Rusted or badly done step flashing means lifting shingles and rebuilding the detail piece by piece. Wide chimneys on the downhill side of a slope need a saddle — also called a cricket flashing — a small peaked diverter behind the chimney that splits water and snow around it instead of letting them pile against the brick. Plenty of GTA chimneys were built without one, and it shows every winter.

What we won't do is bury the problem in tar. A chimney ringed in black roofing cement is a chimney with a history of leaks, temporarily paused — freeze-thaw opens tar within a couple of winters, and each round makes the eventual proper repair messier. We quote the real fix: which layers get rebuilt, whether a saddle belongs there, and whether the masonry itself needs attention first, because flashing anchored into crumbling mortar joints won't hold either.

What this covers

  • Inspection of both flashing layers, the surrounding shingles and the chimney masonry above the roofline
  • Rebuilding of step flashing, interlaced course by course with the shingles on both chimney sides
  • New counter flashing cut into the mortar joints — reglet cut, inserted, mechanically secured and sealed
  • Base and back pan flashing at the chimney's downhill and uphill faces
  • Fabrication and installation of a saddle (cricket) behind wide chimneys where water and snow collect
  • Ice and water membrane around the chimney penetration before the metal goes on
  • Replacement of shingles disturbed during the flashing work, tied cleanly back into the roof
  • A frank report on the masonry — spalling brick or failing crown gets flagged, since that's mason's work

Just need one small job done?

Re-seal chimney flashingFit a chimney rain cap

What affects the price

  • Which layers need rebuilding — resealing counter flashing sits at one end, a full two-layer rebuild at the other
  • Chimney size and position, since wide chimneys and downhill-of-ridge placements need a saddle
  • Masonry condition, because flashing can't anchor properly into failing mortar joints
  • Metal choice, from galvanized to aluminum to copper on heritage work
  • Roof pitch and chimney location — a ridge-line chimney on a steep slope is slow, careful work
  • Hidden rot in the decking around the chimney, common when the leak has run for seasons

Every home is different, so we don’t publish flat prices — the quote is free and based on your actual job.

Chimney Flashing Repair near you

We take quote requests across the GTA. Local pages:

TorontoEtobicokeNorth YorkScarboroughEast YorkYorkMississaugaBramptonCaledonVaughanMarkhamRichmond HillAuroraNewmarketKingWhitchurch-StouffvilleEast GwillimburyGeorginaPickeringAjaxWhitbyOshawaClaringtonUxbridgeOakvilleBurlingtonMiltonHalton HillsHamiltonSt. CatharinesNiagara FallsGrimsbyNiagara-on-the-LakeBarrieInnisfilBradford West GwillimburyNew TecumsethKitchenerWaterlooCambridgeGuelphOrangeville

Common questions

How can I tell if my chimney leak is flashing or the chimney itself?
Pattern helps. Flashing leaks show up during or right after rain, staining ceilings or walls beside the chimney. Masonry problems — a cracked crown, spalling brick, failed mortar — often show as damp inside the fireplace, white staining on the brick, or leaks that persist in winter without rain. A missing chimney cap gives water a straight path down the flue. From photos of the chimney and the stain, we can usually tell you which trade you need.
What is counter flashing and why does my chimney need two layers?
Step flashing seals the roof to the chimney but its top edge can't attach to brick — masonry and roofing move differently with temperature. Counter flashing solves this: metal cut into a mortar joint above, folded down over the step flashing like a lapped shirt collar. Water running down the brick hits counter flashing, sheds onto step flashing, then onto the shingles. Caulking step flashing directly to brick skips the second layer, and it fails within a few freeze-thaw seasons.
Do I really need a chimney saddle or is that an upsell?
Depends on your chimney. A narrow chimney, or one at the ridge, sheds water fine without one. A chimney much past 30 inches wide sitting partway down a slope has a flat spot behind it where water pools and snow drifts — that's exactly where these chimneys leak and rot decking. There, a saddle isn't an upsell; it's the difference between a repair that lasts and one that reappears. If yours doesn't need one, we'll say so.
Can chimney flashing be repaired in winter?
Counter flashing resealing and minor securing, yes, on a dry day. Full rebuilds are harder: shingles are brittle in deep cold, sealants have minimum temperatures, and cutting mortar reglets goes badly on frozen, snow-covered roofs. If your chimney is actively leaking in January, the honest sequence is often a careful temporary seal now and the proper rebuild booked for a thaw or spring. It's the same approach we'd take on our own houses.
How long should chimney flashing last?
A properly built two-layer system in galvanized or aluminum typically outlasts the shingle roof around it — decades. Copper longer still. What cuts that short: sealant joints left unmaintained (they want checking every several years), flashing anchored into deteriorating mortar, and previous tar-over repairs trapping water against the metal. When your roof is eventually reshingled, that's the cheap moment to renew the step flashing, since everything is open anyway.

Ready to sort out your chimney flashing repair?

Tell us what your home needs — a small fix or a full project — and get a free quote.

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