SBS modified bituminous waterproofing membrane


Bituminous waterproofing membrane, modified with selected grade of SBS polymers for excellent waterproofing and low temperature (-20°C) flexibility properties


  • Remains flexible from -20°C to +60°C 
  • Very high resistance against hydrostatic pressure
  • Suitable for applications in deep basements
  • Easy and strong seal on overlaps
  • High mechanical strength and fatigue resistance properties
  • Excellent adhesion on both horizontal and vertical surfaces
  • Easy application on corner details
  • Good dimensional stability under tension

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 surface shall be cleaned thoroughly of all contaminants like dust, traces of curing compound, oil and grease. All surface imperfections, protrusions, structurally unsound and friable concrete must be removed and repaired.


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 that the flow of water is over or parallel to the plies, but never against the laps. All overlaps at the membrane seams shall be installed so as to have «up» slope laps over «down» slope laps. Begin membrane application by unrolling the roll of Bituplus ULTRA FLEX membrane and aligning the side laps. Side overlaps should be a minimum of 100 mm and the end overlaps 150mm.


Bituplus ULTRA FLEX membrane is installed by using a cylinder fed propane gas torch. Use of hand-held roofing torch is recommended as it affords a good control. Begin torching the embossed polyethylene side of the rolled portion of the 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 underlying surface.
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 pressed into the seam using a heated trowel. Any un-bonded areas must be lifted and re-torched.


All internal corners shall be provided with an appropriate cement sand angle fillet. External corners shall be chamfered as per the manufacturer’s recommendations. Prior to the application of the membrane on all internal and external corners, reinforcement strips shall be laid as per the details provided in Fig.3 & Fig.4.


Bituplus ULTRA FLEX membrane shall be protected from getting damaged due to the ongoing site activities and during the backfilling process. Membranes laid on horizontal surfaces can be protected by a cement sand screed (50mm thick). On vertical surfaces the membrane has to be protected with Bituboard. Bituboard can be fixed on the membrane by torching the underside of the board. Please contact our technical service team for specific requirement.