Roof Flashing Calculator
Estimate roof-flashing length and cost from wall junctions, chimneys, skylights, penetrations, overlap allowance and stock-roll coverage.
Default project preview
2 units
Wall junctions
36 ft
Chimneys and skylights
34 ft
Penetration allowance
15 ft
Order length
97.7 ft
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Base flashing length = wall junctions + chimney perimeter + skylight perimeter + penetrations × allowance per penetration. Overlap and waste are added, then packages are rounded up.
FAQ
Roof Flashing Calculator questions
Does this include drip edge?+
No. Drip edge is estimated separately along eaves and rakes using the roof drip edge calculator.
Why enter an allowance for each penetration?+
Pipe boots and small vents use perimeter and detailing material that is easier to approximate as a per-item allowance.
Can one flashing product be used everywhere?+
Not necessarily. Valleys, walls, chimneys, skylights and pipe penetrations may require different materials and profiles.