DRAINAGE CORE

The drainage core is an essential part of the green roof system. This layer allows excess water to move away from the plant root structure and permit storm overflow access to the roof top drain system. The drainage core will be separated from the growing media by a filter fabric layer.

GRS provides many types of drainage systems. Each has a particular application that is driven by the plant palette, roof drainage, depth of media and overall roof garden profile depth.

GRS Aggredrain - is a rotary kiln produced, expanded baked clay lightweight aggregate that complies with all of the applicable standards of the ASTM 0330. It is spread over the Moisture retention payer in a depth of 1 inch minimum.

GRS-D - is a panel type pre-assembled drainage core made of 100% polystyrene, post-industrial regrind. The panel retains water in chambers below a root penetration layer that is fixed to the polystyrene panel. It has a water retention capacity of 1.1 gallons per 10 sq ft. It is 1 inch thick and will resist compression to 9500 lbs psf and provide a storm water flow of 30 gallons per minute per sq ft. It is backed with a 4 oz geo textile fabric to protect the waterproofing layer. GRS-D comes in rolls 4' x50' and uses a fabric overlap to connect adjacent rolls with an underground waterproof seam tape.

Geodren - Drainage core panels developed in Europe where green roofing practices have matured over the last 50 years. Geodren components offer high water retention abilities. The panel profiles are suited for extensive to fully intensive green roof installations.