Step Flashing Calculator
Calculate exactly how many pieces of step flashing you need to properly waterproof a sloped roof intersecting a vertical wall.
Step flashing is installed woven into every single shingle course where a roof meets a wall (like a dormer or chimney). Because standard architectural shingles have a 5-inch to 5⅝-inch exposure, you will typically need about 2.5 pieces of step flashing for every 1 linear foot of wall.
Roof Flashing Estimator
Shingle Exposure Overlap Method
Material Output
Component
Total Required
Individual Step Flashing Tins
26
Using a Step Flashing Calculator
A step flashing calculator takes the guesswork out of ordering pre-bent 4x4x8 tins. When you use a generic roof flashing calculator, it might just give you linear feet, but step flashing is sold by the piece or the bundle (usually 50 or 100 pieces).
- The Weave Method: Unlike continuous roll flashing, step flashing must overlap. Each piece covers the top of the shingle below it and goes under the shingle above it. This means the spacing of your flashing perfectly matches the "exposure" (the visible part) of your shingles.
- Kickout Flashing: Don't forget that at the very bottom edge of your step flashing run, building codes require a specialized "kickout" flashing to direct water away from the siding and into the gutter!