When should roof flashing be replaced, and how much does it cost?
Short answer. Replace roof flashing whenever the roof itself is replaced, and in between when it is rusted through, bent, pulled loose, missing pieces such as a kickout or cricket, or leaking despite resealing. Cost depends on which flashing it is and how much shingle, siding or masonry has to come apart to reach it; during a reroof, new flashing is simply part of the job.
Replace it when
- The roof is being replaced. Reusing old step flashing under new shingles saves little and risks a leak under a brand new roof.
- Rust has eaten through the bottom edge of step flashing or valley metal.
- Counterflashing has pulled out of the brick and resealing no longer holds.
- Pieces are missing, such as a kickout at a roof to wall corner or a cricket behind a wide chimney.
- It was installed wrong: one long L-shaped piece instead of steps, nails in the water path, or joints that depend on caulk.
- Hail dented or split it, or a falling limb bent it.
When resealing is enough
If the metal is sound and only the sealant at a reglet or an exposed nail has cracked, resealing is a reasonable maintenance step. Recheck it each year.
What drives the cost
- Location: a pipe boot or a run of drip edge is quick; sidewall step flashing means removing siding; chimneys may need new cuts in the mortar.
- Pitch, height and access.
- Material: galvanized steel, aluminum, prefinished metal or copper.
- Hidden rot behind flashing that leaked for a long time.
On a replacement estimate, flashing usually shows up as its own line items, such as step flashing by the linear foot, drip edge, and each pipe boot, so you can see it was included. See roof flashing explained, drip edge explained and roof replacement cost in Georgia.