• Drainage sheets of green roofing are of high density polyethylene (HDPE).These sheets have resistance to root infiltration, as well as water storage compartments on their surface. Holes on top of it transfer additional water to the roof surface and exit from the roof slope. Due to the ability to keep water in the compartments, it is possible to prevent dehydration of plants in days without rain or irrigation. It also reduces the thickness of the soil and thus the weight of the green roof. This product is produced in sheets in the size of 50 * 50 cm and 3 cm in thickness in Yekta varagh polymer Yazd company.