General characteristics of extensive and intensive green roofs (adapted from Green Roofs for Healthy Cities and the Cardinal Group, 2006).
Link to this table.
|Growing medium depth||6 inches or less||Portions of the green roof above and below 6 inches, with a minimum of 25% of green roof area above or below 6 inches||More than 6 inches|
|Accessibility||Often inaccessible||May be partially accessible||Usually accessible|
|Fully saturated weight||Low: 10 to 35 lb/ft2 (48.8 to 170.9 kg/m2)||Varies: 35 to 50 lb/ft2 (170.9 to 244.1 kg/m2)||High: 35 to 300 lb/ft2 (170.9 to 1464.7 kg/m2)|
|Maintenance||Varies, but generally lower than for intensive green roofs||Varies||Varies, but generally higher than for extensive green roofs|
|Stormwater management||Best cost-benefit balance||More growing medium and more vigorous plant growth provides marginally greater stormwater volume benefits||More growing medium and more vigorous plant growth provides marginally greater stormwater volume benefits|