Ice-and-Water Shield — Self-Adhered Roof Membrane Guide

Ice-and-water shield is a self-adhering waterproof roof underlayment used to seal vulnerable roof areas against wind-driven rain and ice dam backup.

Ice-and-Water Shield diagram — labeled parts, dimensions, and installation context

What It Is

This membrane is a peel-and-stick roofing underlayment that bonds directly to the roof deck. It helps create a secondary water barrier around nails and fasteners, which is why it is used where roof leaks are most likely to start.

Unlike standard felt or synthetic underlayment, ice-and-water shield is designed to stay watertight even when water backs up under shingles. It is a detail material, but it plays an outsized role in roof leak prevention at edges and transitions.

Types

Common versions include standard eave membrane, high-temperature membrane for metal roofs or hot climates, and wider rolls for valleys and low-slope transition details. Products vary in thickness, temperature rating, and surface texture.

Where It Is Used

Ice-and-water shield is typically used at eaves, valleys, roof penetrations, skylights, chimneys, and other leak-prone roof transitions. In cold climates it is especially important along roof edges where ice dams can force water uphill beneath shingles.

How to Identify One

You usually see it only during roofing work or where shingles have been removed. It appears as a bonded membrane on the roof deck, often with a granular or printed top surface and sealed overlap seams.

Replacement

Replacement usually happens during reroofing or when a roof section is opened for leak repairs. If the membrane was omitted, torn, or installed poorly, the fix often involves removing surrounding roofing so new underlayment can be applied to the deck.

Ice-and-Water Shield — FAQ

Is ice-and-water shield required everywhere on a roof?

No. It is usually required only in certain locations such as eaves, valleys, and other vulnerable areas, and local code determines the exact extent. Full-roof coverage is sometimes used, but it is not standard for every house.

Does ice-and-water shield stop all roof leaks?

It helps prevent leaks in critical areas, but it does not fix bad flashing, failed shingles, or poor roof design. It works best as one layer in a complete roofing system.

Can ice-and-water shield be added without replacing the roof?

Only where the roof covering can be opened up. Because the membrane bonds to the deck under the shingles, it usually cannot be added properly from the surface alone.

Why is my roofer talking about high-temperature membrane?

Some roof areas get hotter than others, especially under metal roofing or in intense sun. High-temperature products are made to resist softening or slipping in those conditions.