General characteristics of extensive and intensive green roofs (adapted from Green Roofs for Healthy Cities and the Cardinal Group, 2006).
Link to this table.

Characteristic Extensive Semi-intensive Intensive
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)
Plant diversity Lower Greater Greatest
Cost Low Varies High
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

This page was last edited on 15 July 2015, at 16:04.

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