The flashing is the first suspect in a roof leak and one of the most common culprits. The field of the membrane is a big, simple surface. The flashing is where that surface meets a wall, a curb, a pipe or an edge, and every one of those meetings is a seam in the building. Each of those seams spends the winter under drifted snow and the spring in a freeze and thaw cycle, and the city rates local weathering as severe.
We prove where the water gets in before we price the repair. Then we price the flashing by the linear foot, and the owner sees the number for each run.
The Call: Reseal, Rebuild or Replace the Run
Flashing repair comes in three sizes. Resealing cleans the joint and renews sealant or termination bar, and it is the answer when the flashing is sound and the sealant is spent. Rebuilding replaces the flashing membrane and counterflashing along a failed run, and it is the answer when the material has cracked, split or pulled away. Replacing the run starts from the substrate: new backing, new flashing, new counterflashing, and often new edge metal at the top.
The size depends on what we find when we open the joint. A termination bar with a dried bead of sealant is a reseal. A flashing that has split at a corner is a rebuild. A wall that has soaked and rotted behind the flashing is a replacement with carpentry. We photograph each opening and write the call for each run. Where the leak has not been traced, we run a hose test in sections, wetting the suspect run first and moving along the wall, with someone inside watching the ceiling. It takes patience, but it turns a suspected source into a proven one, and it keeps the owner from paying to rebuild a run that was never leaking.
What It Costs: By the Linear Foot, With the Wall Behind It
Flashing is priced per linear foot of run, plus corners, transitions and penetrations. A straight reseal is the cheapest. A rebuild adds material, labor and sometimes lift access. A full replacement adds the wall work. The number that surprises owners is the wall: when water has been running behind a flashing, the substrate may be wet, and the wet part must be dried or replaced before the new flashing goes on.
We carry that as an allowance with a unit price, because the extent is unknown until the wall is open. A GC carrying a repair can see the base length, the unit price for substrate work and the trigger for agreeing a change order. Access is its own line when the run is high, such as a parapet on a multistory building. Where flashing is failing in many places, the scope may recommend a recover or a replacement, since the cost of fixing every run approaches the cost of a new system.
What the Code Sheet Says: Drift and Refreeze Load Every Joint
Flashing sits where the city's snow, wind and frost numbers hit hardest. Wind drives snow against walls and builds a drift along the base. When the drift melts, water collects at the joint, and the next night's freeze pushes it into any gap.
A drift of wet snow against a parapet is also a heavy load on the flashing and the wall. The ice that forms at the base can lift the flashing edge, and each cycle widens the gap. Ice barrier is required where it applies, and it protects the first few feet from refreezing water that works under the edge. Flashing that ignores these loads fails in the first hard winter.
Snow depth varies across the region, and so does the exposure. Post Falls averages about 59 inches of snow a year while Wallace averages about 76 and Mullan above 100, so a parapet in the Silver Valley sits behind a deeper drift for longer than one on the prairie. We set the height of the base flashing by that history: a roof that sees drifts to the top of a standard flashing wants a taller one, with the counterflashing lapped over it, so meltwater never has a path behind.
Where It Fails First: Corners, Terminations and Transitions
Failure begins at the places where the material has to change direction or stop. Inside and outside corners crack because the membrane is folded there. Terminations at the top of a wall pull loose when sealant dries and the bar loses its grip. Transitions between wall types, from masonry to metal panel to concrete, open when each material moves differently. Counterflashing, set in a reglet or lapped over the base flashing, loosens when the mortar fails.
We check the base flashing and the counterflashing as a pair, then the wall above it. At Riverbend Commerce Park the tilt-up walls have parapets with caps, and the weak spots are the cap joints and the corners. In downtown Coeur d'Alene, a masonry wall brings counterflashing set in mortar joints, and those joints may need repointing before the flashing will hold. Curbs and pipes follow the same pattern, and the fixes are in the skylight and penetration flashing work.
Alternates: Metal Counterflashing, Reglets and Wall Repair
Choices at this level are simple to price. Metal counterflashing in place of sealant alone. A new reglet cut into masonry. A taller base flashing to clear the expected drift. A termination bar with a better fastener schedule. A coping cap with a continuous cleat. Each is its own line, and each has a different life.
The best alternates remove the weakest link. If sealant has failed three times at the same joint, a metal counterflashing replaces the sealant as the primary barrier. If drifts keep burying a flashing, a taller one changes the water level. If the wall is soaked, a section of wall repair comes first. A leak repair visit finds the source, and the flashing scope follows the evidence.
Schedule and Snow Window: Flashing Needs a Dry Joint
Flashing repair needs a clean, dry substrate and moderate temperatures. Sealants and adhesives have limits, and a joint sealed in a wet cold week will fail. In Coeur d'Alene the best window runs late spring through early fall. Winter leaks get a temporary seal that stops water entry, and the permanent repair waits.
Walk the flashing in September, with the fall drain check, while the joint is still dry enough to read. A termination that is loose in September will leak in March. We pair the repair with a maintenance visit so the next walk checks it, and we log the length of each run repaired with a photo. If the failing flashing is part of a wind damage event, the edge and wall details are repaired together, so the joint is not opened twice.
Commercial Roofing Questions
Is flashing the usual leak source?
It is one of the most common. We prove it by testing and tracing before pricing a repair.
Can sealant alone fix failed flashing?
Only if the flashing is sound. Sealant over cracked or loose flashing buys a season, not years.
What if the wall behind the flashing is wet?
It has to be dried or repaired first. We carry that as a unit-priced allowance.
How long does a flashing repair last?
It depends on the material, the detail and the exposure. We document the repair so it can be checked each season.
Do I need to repair all the flashing at once?
Not always. We rank runs by risk and price each, so the owner can phase the work.