Commercial Asphalt/Flat Roofing

ASPHALT – BUR

A built up roof (BUR) membrane is a continuous, semi-flexible roof membrane. It consists of multiple layers sometimes referred to as a “redundant system” of coated or saturated roll roofing material, and bitumen. The roll roofing material can be felt or sheets such as base, ply and cap sheets, reinforced fabric of polyester, fiberglass, or both used with bitumen of asphalt, polymer-modified asphalt, coal tar or solvent-based asphalt. This is then surfaced with mineral aggregate, bituminous materials, liquid applied coating or a granule- surfaced cap sheet. Membrane flashings typically made of a backer layer or layers of cap sheet are used at the roof perimeter and penetrations. The materials used will depend upon the application.

EPDM

EPDM is elastomeric compound synthesized from ethylene, propylene and a relatively small amount of diene monomer, from which a flexible rubber matrix is formed. This synthetic rubber material can be formulated with great flexibility for use as a membrane sheet roofing. Generally EPDM is manufactured as vulcanized (cured) membrane, although no vulcanized (uncured) EPDM is used as detailing and flashing material. Seams are typically sealed with tape or liquid applied adhesive accordingly to manufacturer’s recommendations. EPDM shows resistance to ozone, UV rays, weathering, abrasion and has good low temperature flexibility.

TPO

TPO roof membranes are a blend of polypropylene (PP) and ethylene-propylene rubber (EPR) polymers. The chemical and physical characteristics allow the single ply membrane to repeatedly soften when heated and harden when cooled. Also, because of their chemical nature, seams are heat welded with hot air. Some TPO membranes are soft and flexible, while other are rigid, although all TPO membranes have positive physical properties, such as heat aging, cold temperature flexibility, puncture resistance and tear strength. All TPO membranes are installed by manufacturer’s guidelines.

APP

APP is asphalt with modifiers added to give either a plastic or rubber properties and qualities. APP is a torch down application. Rolls of APP have a variety of surfacing.

SBS is the same material as APP, but is a different application. Rather than torch down, SBA is either glued or self adhering.