What is ice and water shield?
A self-adhering, rubberized waterproof membrane installed beneath roof shingles at eaves and valleys to block water and ice melt from entering the structure.
Ice and water shield is a synthetic, self-adhesive membrane that sits between the roof sheathing and asphalt shingles, typically installed in high-risk areas like eaves, valleys, and around roof penetrations. Unlike traditional roofing felt, which is breathable, ice and water shield forms a watertight seal that sticks directly to the wood decking.
Connecticut's building code requires ice and water shield in eaves and valleys because the state's freeze-thaw cycles create ideal conditions for ice dams. When snow melts and refreezes at the roof edge, water can back up under shingles. Without this membrane, that water seeps into the attic, causing structural rot, mold, and insulation damage. The shield acts as a second line of defense, preventing water from reaching the interior even if shingles are breached or ice dams form.
The membrane typically extends from the fascia board up the roof slope to a point beyond the exterior wall line of the building (commonly 24 to 36 inches). Valleys require coverage the full width because they channel concentrated water flow. Professional roof replacement and installation contractors in Greater Hartford apply this as code-required protection on new roofs and replacements, making it a non-negotiable component of durable residential construction in the region.