What Is Step Flashing?
Step flashing waterproofs the sloped joint where a roof plane dies into a vertical surface — the side of a chimney, dormer, or second-story wall. Each piece is a small L-shaped metal rectangle: one leg lies on top of a shingle, the next shingle course covers it, and the next flashing piece laps over that, stepping up the slope so every drop of water lands on metal and is shed onto the shingle below. Its vertical leg tucks behind siding or under counter-flashing. It fails when installers substitute one long continuous strip, when pieces are face-nailed through the exposed leg, or when a re-roof reuses bent, rust-thinned pieces. Homeowners see leaks as stains on interior walls below the roofline, or exterior streaking at the roof-wall joint. Correct repair requires lifting siding or shingle courses and re-weaving new pieces course by course — it cannot be fixed from the surface with sealant.
Important Distinction
Note: Step flashing is many short interleaved pieces, one per shingle course; a single continuous angled strip run up a sidewall is not step flashing and will leak as it channels water behind the shingles.
Also Known As
These are the search terms and phrases that commonly refer to this topic, so you can find it however you describe it.
How Step Flashing Relates to Other Topics
A leak along a sidewall usually traces to step flashing that was reused or run as one long strip; each shingle course needs its own woven-in piece, and a single bent strip channels water behind the siding.
Kick-out flashing is the last piece in a step-flashing run, bent to throw water into the gutter - a sidewall's flashing is unfinished without it no matter how well the rest was woven.
Related To Step Flashing
Counter-flashing exists to cover the top edge of step flashing: step flashing moves water off the roof plane, and counter-flashing cut into the masonry keeps water from getting behind it - a bead of caulk substitutes for neither.
Questions about Step Flashing?
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