JOHNS MANVILLE Roofing Systems Group 717 17th Street Denver, CO 80202 Toll-Free: (800) 922-5922 Fax: (303) 978-2318 Web site: http://www.jm.com/roofing 
Bituminous Built-Up Roofing Systems
Conventional bituminous built-up roofing (BUR) membranes have been used for over 100 years and continue to represent a major portion of today’s roofing. The membrane is field fabricated and consists of layers of a waterproofing bitumen alternating with plies of reinforcing felts with an appropriate protective surfacing. The reliability of BUR is enhanced by the redundancy of the plied-in layers of roofing felts. JM manufactures a complete line of fiber glass felts including ply, base and mineral surfaced cap sheets. Ply felts are coated with a high grade asphalt. Two types are available: GlasPly™ Premier and GlasPly IV. Base felts are coated with a filled asphalt and are intended for use as a base sheet in nailed specifications. Our standard base felt is called PermaPly 28™ . Another version, which incorporates a coating of rubber-modified asphalt, is called GlasBase Plus™ . And GlasKap™, a glass mat coated with filled asphalt and surfaced with mineral granules for use as a cap sheet in BUR systems, is also available. Another product, Ventsulation™ Felt, is primarily used as a venting base sheet for applying a new built-up roof over an existing bituminous membrane that is no longer serviceable, or over lightweight insulating concrete substrates. For flashing, a uniquely reinforced fiber glass felt known as GlasTite™ Flexible is available. Of course, various cements, coatings and surfacings are available to make for a complete, single-source system. JM approved asphalt is required for hot applied built-up roofing system applications. Roofing asphalts are available in four types (specified by softening point). The slope of the roof, in conjunction with the climatic constraints, determines the type to be used. The success or failure of a roofing system depends on the use of the proper type of asphalt as called for in the roofing specification.
Sources For Full Information For complete information and specifications on Built-Up, Modified Bitumen and Single Ply roofing products and applications, please refer to the JM web site, www.jm.com. The JM Commercial/Industrial Roofing Systems Manual (RS-7030) is also available. Contact the Regional Technical Services Manager who can be reached through the JM Regional Sales Office nearest you, or the Technical Services Specialists at the Guarantee Services Unit. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||