Best Ice & Water Shield Membranes (2026)

Granulated vs Smooth vs Butyl & Where Code Requires It

Ice and water shield is the one roofing material that still stops a leak after water has already passed the shingles, because it bonds to the deck and self-seals around every nail. Cold-climate codes generally require it from the eave edge up past the interior wall line, plus valleys, chimneys, skylights and low-slope tie-ins. Granulated modified-bitumen membranes give footing under shingles, smooth film-faced membranes let metal panels move, butyl adhesives stay flexible in cold and tolerate heat under metal. This guide covers membrane types, required locations, lap and drip-edge details, exposure limits, and why insulation and ventilation are the real cure for ice dams.