It depends on the type of assembly and the depth of the soil. Saturated Extensive Garden Roofs can range from 110 to 215 kg/m² (22-45 pounds/SF).Saturated Semi-Intensive Garden roofs range from 170 to 440 kg/m² (35-90 pounds/SF), and saturated Intensive Garden Roofs can be anywhere from 170 kg/m² (35 pounds/SF) up to whatever weight the structure can safely hold. Weights will vary by region and design intent.