Analysis of Green Roof Growing Media Porosity

When selecting a growing media for a green roof, a rooftop environment should be distinguished from traditional plant settings. Therefore, it becomes critical that the mediaʹs pore space allows for adequate storage and drainage of water. In this experiment, rooflite™, a certified green roof growing media, was tested at depths of 7.62 cm (3 in) and 10.16 cm (4 in), for drainage and water-holding capacity. The main objective of this analysis is to determine if these two depths will meet the manufacturerʹs recorded values. The depths will also be compared in terms of porosity. When analyzing the results, it was determined that the media could hold and drain enough water on a green roof with a 10.16 cm. depth. In detail, the results indicated that an average of 117.3 mL of water was stored and 35.3 mL of water was drained from a media depth of 7.62 cm (3 in). An average of 153.7 mL of water was held and 46 mL was drained from a media depth of 10.16 cm (4 in). It was concluded that the media depth of 10.16 cm (4 in) had increased water storage and drainage capabilities.