EPDM

We have drain connectors made from high quality EPDM for circular downpipes; which are placed into pre-cast holes along the horizontal deck on the roof or podium. Corner fittings are available for holes on the junction of horizontal and vertical parapet wall, usually running through the wall and into HDPE drainpipe.
http://www.wallbarn.com/products/roof-outlets-vents/roof-outlets-collars/epdm/