Step flashing
What is step flashing?
The L-shaped metal pieces that waterproof where a roof meets a wall or chimney — often reused improperly or left off the scope.
Definition
Step flashing is a series of small L-shaped metal pieces woven into the shingles where a roof plane meets a vertical surface like a wall or chimney. Each piece overlaps the one below to channel water away from the seam.
Best practice and many codes call for new step flashing on a reroof, but scopes often assume it’s reused or skip it entirely. Reused flashing is a common source of leaks, which makes new flashing a defensible supplement.
Where there’s a wall or chimney intersection, step flashing belongs on the estimate. Photos of the affected sidewalls back up the line item.
Related terms
Drip edgeA metal flashing installed along the roof’s edges that directs water away from the fascia — and a line item carriers frequently leave off.Ice-and-water shieldA self-adhering waterproof membrane installed in vulnerable areas to prevent leaks from ice dams and wind-driven rain.Supplement line itemsThe specific items added to a claim through a supplement — the missed materials, code work, and underpriced entries that bring the scope up to the real job.Roofing supplementAn additional request to the insurance carrier for money the original scope left off — extra line items, missed materials, or code-required work.