Ice and water shields on roofs are designed to prevent leaks on the roof deck from rain and the formation of ice dams caused by melting snow and ice. Ice and water shields also act as an extra layer of protection at the rake edges and eaves of a roof.
Ice and water shields are highly effective on flashing areas that are susceptible to leaks, such as dormers, skylights, chimneys and vent pipes. Shields give the roof a seal that's watertight and can help a homeowner avoid having to make expensive repairs to the roof due to stains accumulating on the ceilings and walls inside of the home.
Ice and water shields are also used to improve a home's exterior appearance. Shields made with fiberglass reinforcement are more resistant to buckling and wrinkling and are better able to lay flat underneath shingles. Another advantage of water and ice shields is they can help reduce installation time because the release film on the split-back can be taken off in sections.
Ice dams pose a significant risk to homes because they can cause water damage to the interior of the home as well as the roof's structure. With enough water damage from ice dams and leaks, there's a chance that mildew and mold can start to form inside of the home.