How long is a roll of ice and water shield, and how far does one go?
Short answer. Most full rolls of ice and water shield are about 36 inches wide and roughly 65 to 75 feet long, covering about 200 to 225 square feet, while smaller rolls of about 33 to 36 feet cover around one square. After side and end laps, a roll covers less than its label says, so a typical full roll lines roughly 60 to 70 feet of valley.
Common roll lengths
- About 75 feet: roughly 225 square feet per roll at 36 inches wide.
- About 65 to 67 feet: roughly 200 square feet, or two squares.
- About 33 to 36 feet: roughly one square, handy for repairs and small jobs.
Length and coverage are printed on the roll label, and brands differ, so check before ordering.
How far one roll really goes
- Valleys: one full-width sheet centered in the valley, so a 66 foot roll lines a little over 60 feet of valley after end laps.
- Eaves: one row per 36 inches up the slope; where two rows are needed, each foot of eave uses two feet of roll.
- Walls and pipes: cut pieces, with more waste from trimming.
- Side laps: about 3 to 3.5 inches on each row cut the effective width to roughly 32 to 33 inches.
Handling long rolls
Long sheets are hard to place straight, especially in summer heat when the adhesive grabs on contact. Installers often cut long runs into shorter pieces and lap the ends by about 6 inches. In a valley, starting at the bottom and working up keeps every lap shedding water.
To figure total rolls for your roof, see how roofers measure a roof; for where membrane belongs, ice and water shield in Georgia.