The drainage channel is one of the key advantages of the Riverclack^® system. In storm conditions, water can slow or come to a standstill as it runs off the roof. With nowhere to go, the water level then rises and the profile is quickly submerged.

With Riverclack^®, the drainage channel captures any water that might penetrate the side lap and carries it away to the gutter, eliminating the risk of leaks into the building.

By eliminating the risk of leakage, the Riverclack® drainage channel allows for lower roof pitches and longer panel lengths. In 2009, CA Group Ltd. (UK) installed almost 1,000 Riverclack^® panels on the roof of the Prologis - Marks & Spencer distribution center in Bradford, UK. The panels were 178m (584ft) long with a roof pitch of just 1.5°.

Indeed, after steelwork deflection at panel ends, the Riverclack^® system can be installed on roofs with pitches as low as 0.28°.

In a hugely demanding test for any product, a pool was built using Riverclack^® 550 panels, with no additional side lap sealant, as the base. The pool was then filled with water, submerging the Riverclack^® system, and left for 45 days during which time not a single drop of water leaked through. In fact, when the system was dismantled, even the integral drainage channel contained just a few drops.