The “NUOVA” ANTI-BACKUP ROOF DRAIN IN PVC-P is one of the most valid systems for connecting rainwater pipes and drains on flat roofs, gutters of multipitched roofs and industrial buildings. It is used for application on roofs waterproofed with PVC-P membrane. This particular item has been studied right down to its smallest details so as to optimize its characteristics, in fact, it has a 170×30 mm diameter deep head which increases the drainage capacity up to 45% compared to a standard drain. The total funnel length of 330 mm allows for use with thicker substrates thus avoiding the need for any intermediate joints and when inserted into the spigot of down pipe permits a constant and continues flow without losing any of the capacity of the downpipe, it can also be fixed into position previous to installation of the downpipes. The drain is made of soft, flexible and UV stabilized PVC-P. It offers high physical, chemical and technical properties as well as a flexible product. It is highly resistant to UV rays, ozone and other atmospheric and chemical agents. It can be used in a wide temperature range and is extremely flexible at low temperatures, it is stable over time thanks to the physical and mechanical properties, which therefore assure maximum performance throughout its lifespan. It has been proved that this roof drain can discharge up to 45% more than a normal drain of the same diameter. The drain consists of a truncated body available in various diameters solidly attached to a smooth flange. The stem piece of the unit has two or more strategically placed circular rings which face outwards and when forced into the drain pipe form a perfect seal. The seal rings are compressed upwards when inserted into the downpipe and thanks to this pressure fit, they guarantee optimal seal with any type of pipe and prevent the passage of water vapour or backup of water into the roofing system. This is particularly important where insulation is involved as it could compromise the insulation its self, factor that constitutes one of the main problems in roof waterproofing. It is highly recommended to use the 200 mm diameter gravel grate directly connected to the slotted ring, the ring ha three slots which allow for the regulation of the height in case of layer variations in the waterproofing system.