DRAINAGE TYPE: Drainage Type P utilizes drainage plates, waffled plastic sheets that store water above and drain water below. Drainage plates are lightweight, are easy to install, and are available in three sizes to meet the drainage and water storage requirements of almost any green roof. Drainage Type G utilizes a lightweight, porous inorganic granular media embedded with slotted plastic triangular drainage conduit. Granular media is heavier and is more labor-intensive to install than drainage plates, but provides a superior environment for plant root growth. Drainage Type M utilizes “drainage mat” a multi-layer fabric mat that combines soil separation, drainage, and protection functions into one product. This system is the fastest to install and creates the thinnest and lightest green roof assembly. However, its water storage and drainage capacity is limited, so it is primarily used for sloped roofs not suitable for Drainage Type P or Type G.