Underlayment

The roof deck should be covered with a layer of roof underlayment. The underlayment is a water-resistant layer under the shingles throughout the roof to protect the roof from moisture. In some areas, it is common to use an additional waterproofing membrane over the underlayment. Underlayment depends on the type of roof shingles. Asphalt felts are typical underlayment for manufactured homes. Asphalt felts consist of heavy felt paper saturated with asphalt or coal tar which are usually available in 15-lb, 30-lb, and 60-lb with 36-inch wide rolls. Special types of underlayment may be required in specific climate conditions. For example, in areas with less than 25F average daily temperature in January, Ice dam protection is recommended. It is common to use 15-lb felt in manufactured homes.