APP modified bituminous waterproofing membrane


BITUPLUS PX membrane is a superior grade plastomeric waterproofing membrane, manufactured from a rich mixture of bitumen and selected app (atactic poly propylene) polymers blended together to obtain excellent heat & uV resistance and waterproofing properties.the polymerized bitumen is coated on to a dimensionally stable reinforcement core of non woven spun bond polyester rot-proof fabric.the membrane has excellent mechanical properties and is highly resistant to fatigue and is designed for use in structures exposed to high temperatures.


  • Excellent resistance to positive water & vapor pressure
  • Good heat resistance
  • Good dimensional stability under tension
  • Can accomodate structural movements because of excellent flexibility
  • High puncture and fatigue resistance
  • High tensile and tear strengths
  • Resistant to water borne chemicals

This TDS is applicable for the United Arab Emirates only. Please contact your local Polybit sales office for the available TDS in your region

Step by step

The application temperature should be between 5°c to 55°c. Application procedures may vary slightly depending upon site conditions. the general recommended guidelines for the application of the waterproofing system is as follows:


The surface shall be cleaned thoroughly of all contaminants like dust, traces of curing compound, oil and grease. All surface imperfections and protrusions shall be removed and repaired. Structurally unsound and friable concrete must be removed and repaired with a suitable POLYCRETE* concrete repair mortar.


Apply POLYPRIME SB* (solvent based primer) @ 4-6 m²/l to a clean smooth and dry surface by brush, roller or spray. Allow the primer to dry prior to the application of the membrane. As the viscosity of the primer is low, it easily penetrates into the concrete pores which promotes the adhesion between the membrane and the concrete surface. In addition to that the primer also acts as a binder for the dust which gets accumulated on the concrete surface even after cleaning.


Start the installation of all membrane plies from the low point or drains, so the flow of water is over or parallel to the plies, but never against the lap. All overlaps at the membrane seams shall be installed so as to have "up" slope laps over "down" slope lap. Begin membrane application by unrolling the roll of BITUPLUS PX membrane and aligning the side laps. Re-roll the roll halfway and stand on the unrolled portion to prevent shifting. Side overlaps should be a minimum of 100 mm and the end overlap 150mm.


BITUPLUS PX membranes are installed by using a cylinder fed propane gas torch. Use of hand-held roofing torch is recommended as it affords a good control. If multiple burner torching machines are utilized, care must be taken to ensure the application of uniform heat and avoid overheating of the membrane. Begin torching the embossed polyethylene side of the rolled portion of the membrane. Proper torching procedure involves passing the torch flame in an ”l” pattern applying about 75 percent of the heat across the coiled portion of the roll and 25 percent across the substrate, including the lap area of the previously installed membrane. As the membrane is heated the embossing starts to melt away exposing a shiny bitumen surface. Roll forward the membrane and press firmly with the boot or roller against the substrate to bond well. The propane flame should be moved from side to side and up the lap edge while the membrane is slowly unrolled and adhered to the surface. Subsequent shift of the roll shall be avoided after heating has begun. When one end is complete, re-roll the opposite end not yet torched, and install in the same manner. As subsequent rolls are installed, heat is applied to both the roll and the exposed laps of the membrane being overlapped onto. Be sure to heat the entire roll evenly, not just the lap areas, with extra concentration at the laps.

CAUTION: do not over torch the membrane as this will expose the reinforcement and cause damage to it.


heat both the overlaps and use round tipped trowel to seal the overlap. Adequate heat is confirmed when a uniform flow of melted bitumen compound flows evenly in a bead that oozes from the applied membrane’s edges. Excess compound should be smoothened and pressed into the seam using a heated trowel. Any un-bonded areas must be lifted and re-torched. Do not attempt to reseal by torching the top surface of the membrane.


Flashing details are accomplished using cut pieces of BITUPLUS PX membrane in combination with appropriate prefabricated flashing components. The same side lap and end lap rules apply to flashing details as to field membrane. All angles and abutments should be sealed with extra care to ensure full bonding. An appropriate flashing membrane (mineral surface) shall be lapped with the base membrane and taken up on the parapet wall and tucked into a groove cut into the concrete. The grooves will be sealed with a suitable mastic sealant (BITUMASTIC)*.