| 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 |