COLPHENE BSW UNILAY HP is a waterproofing membrane composed of a select blend of highperformance flexible SBS elastomeric bitumen combined with a ultra high strength double reinforcement system (heavy duty non-woven polyester associated with an additional specific fleece).


The topside is covered with specially engineered carbon dioxide crystals and the underside is covered by a thermofusible plastic film. Thanks to its special formulation and composition COLPHENE BSW UNILAY HP has excellent, continuous and homogenous bond to poured structural concrete, increased resistance to hydrostatic pressure and superior resistance to tears and punctures.
Its unique design, including the DUO SELVEDGE technology, allows welding of side laps using a torch or a hot air gun. COLPHENE BSW UNILAY HP is a pre-applied membrane designed for horizontal blind side waterproofing applications (below grade and tanking works).


COLPHENE BSW UNILAY HP is installed loose laid on the concrete slab or compacted soil. To prevent overly thick membranes, stagger the end laps by a minimum of 300 mm. Side lap joints must be a minimum of 120 mm (see DUO SELVEDGE rubric below) and end lap joints must be a minimum of 150 mm. Membrane overlaps are torched-on. All angles changes (inside and outside corners) and others details must be reinforced by heat-welding on additional 300 mm piece of COLPHENE BSW UNILAY HP centered on the angle. COLPHENE BSW PROTECT’R, as a protection layer, is not necessary over the COLPHENE BSW UNILAY HP if the reinforcement steel bars installation and pouring of the concrete slab are carried out carefully.
Over the entire width of DUO SELVEDGE, 40 mm of the surface is covered with exposed sticky bitumen. The remaining surface of the selvedge (80 mm) is covered by a thermofusible plastic film to seal overlap by torch-on techniques.


  • Thickness: 4,5 mm (-5% ; +5%)
  • Dimensions of the roll: 8 m x 1 m
  • Weight of the roll: about 40 kg

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