ICE & WATER SHIELD
Ice and water shield leak barriers prevent leaks along the eaves and valleys of the roof, where ice dams can back water up underneath the shingle. An ice dam occurs when water builds up behind a blockage of ice. An ice dam can occur when snow accumulates on the roof of a house. Heat conducted through the roof substrate and warm air from the attic warms the roof and melts the snow on those areas of the roof that are above living spaces, but does not melt the snow on roof overhangs. Melt-water flows down the roof, under the blanket of snow, onto the eave and into the gutter, where colder conditions on the overhang cause it to freeze. Eventually, ice accumulates along the eave and in the gutter. Water from the melted snow accumulates behind the ice as it cannot drain properly through the ice on the eave and in the gutter, resulting in leaks to the roof space resulting in damaged ceilings, walls, roof structure and insulation. Valleys and wall edges are more prone to leaks as well, due to higher water volume. The ice and water shield leak barrier is a rubberized waterproof membrane that adheres to the decking of the roof along the eaves, edges, and valleys and prevents water from reaching the roof decking and leaking into the house.
