What is the function of an ice and water shield?

• A. To provide an extra waterproof layer at eaves and other vulnerable areas to prevent water intrusion from ice dams
• B. To insulate the attic
• C. To provide decorative trim
• D. To vent moisture

Answer: (A)

This item tests understanding of what an ice and water shield does. Its job is to provide an extra waterproof layer at the eaves and other vulnerable areas where ice dams tend to form. In cold climates, meltwater at the roof edge can refreeze and push water back under shingles; the ice and water shield is a self-adhesive membrane installed on the roof deck to seal around fasteners and resist water intrusion, acting as a secondary barrier if the primary shingles are compromised. That’s why it’s placed at the eaves and other vulnerable spots, to prevent water from penetrating into the attic or ceiling.

It isn’t meant for insulation, decorative trim, or venting moisture, so those functions would be handled by separate systems or materials.