How long does roof flashing last?

No source we checked gives one lifespan for roof flashing, because it depends on the metal, the sealant, the roof it sits on and how it is installed. Metal flashing can outlast the shingles around it. Rubber pipe collars and sealant joints tend to wear out sooner. The practical rule is to inspect flashing twice a year and plan to renew it whenever the roof covering is replaced.

What decides how long flashing lasts

• The material. Flashing is thin metal or roll roofing. Metals differ in how they resist corrosion, and the right choice depends on the roof covering. Ask a roofer to name the metal and gauge in a written quote rather than saying "flashing".
• Sealant versus lapped metal. Flashing that depends on caulk or roofing cement is only as good as that bead. VELUX describes its skylight flashing as designed to shed water without relying on sealants that can break down over time.^[2] A joint held together with surface sealant needs rechecking far more often than a well-lapped metal joint.
• Rubber parts. Plumbing vent boots have rubber collars that sit in the sun. They often crack before the metal does. See why a plumbing vent boot leaks.
• Installation. Flashing that is tucked in correctly with the shingles above and below it keeps shedding water. A poorly lapped piece can leak within a season.
• Exposure. Coastal salt air, heavy shade that stays damp, steep wind-driven rain and clogged gutters all shorten the life of the metal. For galvanized steel roofing, the USDA Forest Service says to expect fewer years in coastal climates.^[1]
• Movement. Chimneys, walls and dormers settle and flex slightly. Cracked mortar or lifted counterflashing is usually where a joint opens first.

Flashing and the age of the roof

The surrounding roof is a useful guide. The USDA Forest Service lists a heavy, laminated architectural asphalt shingle at a 20- to 30-year lifespan.^[1] If your roof is that old, the flashing was probably installed with it, and some may have been reused when the roof was last replaced. Reusing old flashing under new shingles saves money only if the metal is sound and the details can be redone properly.

Shingle warranties do not usually help here. One Owens Corning lifetime warranty states that it does not cover non-Owens Corning® roofing components, such as flashing, fasteners, pipe boots, and wood decking.^[3] Do not assume a long shingle warranty means long flashing life.

How often to check

The USDA Forest Service says flashings should be checked twice a year when the roof is inspected and the gutters are cleaned.^[1] It also says many apparent roof leaks are really flashing leaks.^[1]

You can do part of that check from the ground or an upstairs window. Binoculars show rust streaks, lifted edges, gaps where metal meets a chimney or wall, and old sealant that has split. Inside, look for new stains on ceilings and walls near chimneys, dormers and vents, and for damp insulation in the attic. Stay off the roof. OSHA's roofing guide says falls are the leading cause of death in the construction industry.^[5]

When to replace instead of repair

Signs that a section has reached the end of its life: rust that has eaten through the metal, repeated leaks at the same spot, caulk layered over earlier caulk, or flashing that has shifted away from the chimney or wall. In those cases a roofer may recommend renewing that flashing instead of patching it. When a roof is replaced, ask the quote to say which flashings are new and which are reused. Pricing is covered in how much flashing repair costs in Virginia.

When to call a licensed pro

Inspecting, resealing, repairing and replacing flashing is roofwork. In Virginia the Board for Contractors defines roofing as the installation, repair, removal, or improvement of materials common to the industry that form a watertight, weather resistant surface for roofs and decks.^[6] DPOR's hiring guide says that when the work is valued at $1,000 or more, a valid Virginia Contractor’s License is required for the license category in which the contractor is to work.^[7] Look up the roofer on DPOR's licence lookup before you pay a deposit.

A building permit may be required for a roof replacement, so ask your local building department.^[4]

To learn what flashing is and where it goes, read what roof flashing is. To find the right trade, see who repairs chimney and roof flashing. Browse all roofing answers or roofing businesses near you.

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