Drip Edge Calculator
Calculates 10-foot perimeter drip edge flashing pieces for eaves (installed under underlayment) and rakes/gables (installed over underlayment), including 2" end lap joints and corner miter cuts.
Formula
Total Pieces = Ceil(((Eaves + Rakes) × (1 + Waste %)) ÷ 10 ft)
1. Total Net Linear Ft = Eaves + Rakes 2. Gross Linear Ft with Waste = Total Net Linear Ft × (1 + Waste %) 3. 10-ft Pieces to Order = Ceil(Gross Linear Ft ÷ 10 ft/piece)
Inputs
- Total Eave Length (Gutter line perimeter)
- Total Rake / Gable Slope Length
- Drip Edge Profile
Worked example
Flashing a complete roof perimeter with 10-foot T-style aluminum drip edge.
Outcome: Net length is 180 linear ft. Adding 10% overlap waste equals 198 linear ft. Dividing by 10 ft per piece gives 19.8 pieces, rounding up to 20 full 10-foot pieces.
Is drip edge legally required by residential building code?
Yes! Under IRC 2018/2021 Section R905.2.8.5, drip edge is mandatory on all residential asphalt shingle roofs at eaves and gable rake edges to prevent water capillary action from rotting the roof deck and fascia board.