APP index page

Product Overview

Revised: March 27, 2007

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 (+300°F 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
Over 17 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.