Missing or poorly installed flashing: what it is, how serious, what it costs

Flashing is a strip of metal (aluminum, galvanized steel, copper) or membrane installed where two surfaces meet and water could get in: around a chimney, where a roof meets a wall, around plumbing vents, above doors and windows. It sends water over the joint instead of letting it in.

Reports often say “missing flashing”, “improperly installed flashing” or “open sealant at the flashing”. In a French report, the word is « solin », and « solin de rejet » is the drip cap over a window or door.

It depends on where it is and what shows inside. Dried sealant around flashing is maintenance. Missing flashing above a window or at the base of a chimney lets water behind the siding or into the attic, often unseen for years, and the wood eventually rots.

That is why it shows up in all three lists: “Fix first” when there are water marks inside, “To check” when the inspector could not see everything (a roof viewed from the ground, for example), “Can wait” when it is sealant to redo.

Installing or redoing the flashing at one opening: $400 to $900. Redoing the flashing and seal at the base of a chimney: $400 to $1,100. Adding flashing where a deck meets the wall: $300 to $700.

If water has been getting in for a long time, add the repair of the damaged wood or siding behind it, which a contractor can only price once the wall is open.

These are ballpark figures for Quebec, to be confirmed with quotes.

1. Where exactly is flashing missing, and is it real flashing or only sealant?
2. Did you see water marks inside below that spot: attic, ceiling, window frame?
3. Did you walk the roof, or look at it from the ground?

Does your report mention flashing? Upload it: in five minutes, I tell you what comes first, what to have checked and what to ask the seller.

No. Caulking fills a joint and dries out over time. Flashing is a piece of metal or membrane that diverts water; sealant only completes it.

A roofer for the roof and chimney, a siding contractor for windows and walls.