Product Overview

Cap Sheets

Base Sheets

Products Page

Revised:  August 06, 2013

BITEC APP modified bitumen membranes are composed of select APP (ATACTIC POLYPROPYLENE) synthetic polymers blended with distilled asphalt and reinforced with "spun-bond" polyester fabric. BITEC APP membranes are always installed by heat welding unless otherwise specified in our installation manual. They have the following characteristics:



BITEC APS-4T, a smooth surfaced APP modified bitumen membrane can be coated or left uncoated according to the specific system specification. BITEC APM-4T, a mineral surfaced APP modified bitumen membrane contains factory installed roofing granules which eliminate the need for installing an additional surfacing such as a roof coating.

  • High melting temperatures (+300F softening point)
  • Excellent flexibility at low ambient air temperature
  • High resistance to thermal
    degradation and slide
  • Resists ultraviolet light degradation
  • Effectively adheres to prepares substrates
  • Resistance to most acids
    and bases
  • Impermeability to water

BITEC APP modified bitumen
membranes may be used to waterproof prefabricated concrete roofs, roof systems with metal and wood decks, thermal insulation, paved roofs or walkways, foundations, and constructions such as multi-story parking decks.


APP Cap Sheets are Reinforced with Continuous Filament Polyester

Continuously extruded polyester threads are needle-punched and then chemically bonded with synthetic resins. This process creates a durable material, vastly different from fabrics using cut fibers. The reinforcement has the following characteristics:

  • Excellent flexibility

  • Resistance to perforation

  • High elasticity

  • High mechanical strength

  • Fatigue resistance

  • Resistance to shear stress
    and organic deterioration.

  • Dimensional stability

  • Resistance to heat and
    aging caused by the UV light

  • Years of proven field performance in all climate areas

Mineral surfaces reduce thermal and ultra-violet light degradation, and slow the normal processes of membrane aging.

BITEC Membranes that are applied
by heat welding contain a
polypropylene and/or polyethylene
covering to prevent roll blocking
and provide a site indicator for
proper welding temperature. These
films will melt, allowing the APP
modified bitumen compound to
adhere to itself and the substrate
being bonded to.

Basic tools required for application of BITEC APP membranes are a propane gas fired roofer's torch, a round nose roofer's trowel, a hook-blade roofer's knife and a pair of fire resistant gloves.


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