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Abstract
Self-adhering bituminous membranes have been used as underlayments in steep slope (greater than 2:12) roofing for many years. When applied as an underlayment, they are primarily used to help prevent water entry from ice dams at the eave areas of shingled roofs in cold climates. When used as ice dam protection, the underlayment is typically installed directly to the deck surface from the eave’s edge to a point at least 24 inches (measured horizontally) inside the exterior wall line of the building prior to application of the shingles. If the membrane is not wide enough to reach that point, install additional course(s) of membrane as needed, overlapping the previous course by 2 inches or as specified by the manufacturer. Self-adhering bituminous membranes are required by building codes to meet the requirements of ASTM D1970, and newer codes require these products to have a label indicating compliance with ASTM D1970.
Self-adhering bituminous membranes have been used as underlayments in steep slope (greater than 2:12) roofing for many years. When applied as an underlayment, they are primarily used to help prevent water entry from ice dams at the eave areas of shingled roofs in cold climates. When used as ice dam protection, the underlayment is typically installed directly to the deck surface from the eave’s edge to a point at least 24 inches (measured horizontally) inside the exterior wall line of the building prior to application of the shingles. If the membrane is not wide enough to reach that point, install additional course(s) of membrane as needed, overlapping the previous course by 2 inches or as specified by the manufacturer. Self-adhering bituminous membranes are required by building codes to meet the requirements of ASTM D1970, and newer codes require these products to have a label indicating compliance with ASTM D1970.
Date
4/2024
4/2024
Author(s)
Page(s)
1-2
1-2
Keyword(s)
underlayment; ice; dam; shingled
underlayment; ice; dam; shingled