Roofing sheet (high-polymer roof waterproofing membrane)
The half-span roof constructed in the 60s consists of a combination of aluminium elements and glass skylights. Due to the incident natural light, the wiredglass window areas of the half-span roof provide optimum lighting conditions for the rooms below. The
waterproofing system had started to leak on account of the severe weather conditions and the relatively steep pitch, and therefore had to be refurbished.
The high-grade PMMA waterproofing resin Wecryl 230 / 230 thix is designed for creating durable and reliable roof waterproofing systems and consequently ideal for refurbishing a half-span roof featuring the concave form of HP (hyperbolic paraboloid) shells. Since the resin is applied as a liquid, it allows a seamless waterproofing system to be created that securely incorporates the roof outlets and rows of windows.
First the existing waterproofing membrane had to be cleaned thoroughly, the gullies installed (with the PVC drain flanges being abraded to provide a good key for the waterproofing resin) and the open sections masked off (otherwise the waterproofing resin could run into the open sections and trigger reaction problems as
well as attack the thermal insulation underneath). The horizontal area was then waterproofed with Wecryl 230 and an embedded fleece. Two layers of fleece, each 70 cm wide and with an overlap of 5 - 10 cm, were used. The thixotropic Wecryl R 230 thix was used to waterproof the vertical faces (1.40 cm).