What type of window flashing tape should I use?

Self-adhered flashing tapes like DuPont FlexWrap, Henry Blueskin, or 3M All Weather Flashing are most common. Use a product compatible with your housewrap manufacturer.

Window Flashing Calculator

Calculate total linear feet of window flashing tape needed for all your window openings.

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Enter Your Measurements

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How to Use This Calculator

1Count total number of windows.
2Enter average window perimeter (typical 3×4 window = ~14 ft).
3Click Calculate.

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About This Material

Window flashing tape (self-adhered flashing membrane) seals the rough opening around windows to prevent water infiltration. Install in a specific sequence: sill first, then jambs, then head flap.

Installation Tips

•Install sill flashing first with a back-dam fold.
•Lap jamb flashing over sill flashing.
•Lap head flashing (headband) over housewrap.
•Use a J-roller to firmly embed tape.

Common Mistakes to Avoid

Installing in wrong order (head flashing must lap over housewrap).
Not using a J-roller — adhesion is critical.
Skipping the sill flashing — most window leaks start at the sill.