Roof underlayment is used in nearly all building systems,
both residential and commercial. Felt paper is more commonly used in the
residential sector due to its inability to be used in low slope, or flat, roof
systems that are common commercial buildings. Felt paper per roofing square is considerably
cheaper than its self adhering counterpart. However, the warranty and water protection
provided by the self adhering membranes is going to be greater. In some situations,
a combination of both products will be used on one roofing system. Felt paper will be used in the large, sloped
areas where water collection and ice damning are uncommon. In addition, self
adhering products will be used in valleys and high traffic areas in which water
collection is a concern. Both systems must be able to withstand, and protect
against, water damage as well as wind up-lift, wind driven rain and ice damming.
In high wind areas such as hurricane zones,
and colder climates in the North east, the self adhering products are preferable
due to their high level of performance.
