Water can enter above the visible mark, move behind siding or masonry, follow underlayment and decking, and appear beside the junction rather than directly below it. We start with when the leak appears, which weather direction makes it worse, whether snowmelt or ice is involved, and what previous patching was attempted. Interior or attic evidence can help when access is safe, but the exterior review still needs to include the roof covering, flashing sequence, upslope drainage, fasteners, mortar joints, siding, and nearby penetrations.
Step flashing at a sloped roof-to-wall joint works differently from counterflashing at masonry, valley metal under shingles, a flexible pipe boot, a skylight kit, drip edge at the eave, or a parapet transition on a flat roof. Each detail has to collect and return water to the drainage plane while remaining compatible with the roof material. The inspection identifies the specific junction, the visible failure, how water is expected to leave it, and whether the existing detail can be repaired without opening a larger section of roof.
A chimney intersection may include step flashing woven with the shingles, counterflashing set into or attached to the masonry, a back pan or saddle on the upslope side, sealant joints, and the brick, mortar, cap, and flue above. Water can enter through the roof junction or through deteriorated masonry and emerge in a similar place indoors. We define the roofing work and identify visible masonry concerns, but chimney rebuilding, repointing, cap work, or flue repairs may require a qualified masonry or chimney contractor.
Compatible sealant can be appropriate at a designed joint or as temporary protection, but coating the face of failed flashing does not restore the hidden laps, drainage path, or damaged roof material below it. Thick layers of old caulk can also conceal the original detail and make later repair harder. Where practical, the lasting repair exposes enough of the junction to understand how it was assembled, removes failed or incompatible patching, corrects the metal or membrane transition, and reinstalls the surrounding roof covering in the proper order.
On a shingle roof, a flashing repair may require carefully lifting or replacing nearby shingles, checking underlayment, and restoring fastener locations so water continues to shed over each layer. On a flat or low-slope roof, the repair method depends on membrane type, condition, moisture extent, and compatibility at curbs, drains, parapets, equipment, and edges. A sound metal piece cannot stop a leak if the surrounding shingles, membrane, decking, or wall finish no longer provide a workable tie-in.
An isolated open lap, damaged pipe boot, displaced counterflashing, limited wall intersection, or small valley defect may support a focused repair. Widespread corrosion, repeated patching, deteriorated masonry, soft decking, multiple failed transitions, or a roof near the end of its useful service life can make a larger re-flashing or replacement scope more sensible. We separate the immediate leak path from the broader roof condition so the quote explains what will be opened, retained, replaced, and left outside the work.
The City of Toronto lists replacement of existing roofing material without structural work among projects that generally do not require a building permit. Structural or material alterations, chimney or fireplace work, and other changes can follow a different path. A flashing repair that stays within the existing non-structural roof assembly is not the same scope as rebuilding a chimney, altering framing, changing a roof opening, or reconstructing a wall. The property owner should confirm the exact proposed work with Toronto Building when the boundary is unclear.
A useful repair record identifies the observed condition, the flashing or transition addressed, surrounding material opened or replaced, concealed limitations, related-trade items, and photos before and after work. Watch the interior through the next rain, wind direction, thaw, or snowmelt that previously triggered the leak and report continued moisture promptly. Tarion’s Ontario construction guidance treats roof and associated flashing as one water-control system and states that defects allowing water penetration through roofs or flashings should be repaired.
