Underground Journal

Roofing Felt

Roofing felt is a petroleum based underlayment that is used as a waterproof membrane for numerous roofing systems. The felt is a fibrous paper material and it is produced in several standard weights or thickness and packaged in rolls that vary in square foot coverage depending on the weight.

In hot application roofing systems the felt is rolled out and built up in several layers that are each sealed with hot asphalt to create the waterproof membrane. This is topped with a medium density roofing gravel or composition roofing that protects the membrane.

With shingled roof systems the roofing felt is applied directly to the roof seathing using staples or roofing nails. This felt is manufactured with overlap lines that adhere to certain specifications and serve as a guide for the proper overlap of each course. The felt used for wood shakes is most often a heavier weight than the felt used for standard shingles, however, the heavier weight can be used in place of a lighter felt in any wood shingle application.

A single layer of felt under wood shingles or shakes has been the standard of the industry for some time. However many roofing contractors are now applying a double layer of felt to ensure the longevity of the moisture membrane and provide a more viable warranty for the installation. This is also the case with conventional composition shingle roofing as well. The additional layer of roofing felt provides a more reliable system in terms of longevity and it benefits the customer service agreements that are included in the contractors warranty for the installation.

Where clay or concrete roofing systems are employed one or more layers of roofing felt are applied directly to the roof sheathing as well depending on certain requirements. The top layer in a tile roof system has a sealed asphalt coating that serves as a secondary shield in addition to the roofing tiles.

Roofing felt can be purchased through a roofing supply or most building materials outlets. The weight of the felt being used and the manufacturing specifications should conform to ATSM guidelines and local building code requirements.

Resources: For more information and tips for your home renovation projects, visit www.besthomerenovation.com.

(0) Comments Permalink