|Agave are drought, salt, wind, heat and hurricane tolerant, but they will add weight to a green roof!|
|Potential Florida Green Roof plant or potential roof problem?|
Some succulent plants develop swollen root tubers for water and nutrient storage. Additional water means heavier weight. Moreover, some of these roots grow in a very aggressive fashion and can damage an underlying single ply membrane or asphalt shingle roof.
|Potential green roof plants have also have aggressive root systems that can damage single ply or shingles|
Problems arise when these overgrown plants present weight issues with respect to the loading capabilities of a supporting roof structure. An extensive green roof with smaller plants may weight twenty to thirty pounds per square foot or 100 - 150 kg/sm. The same extensive green roof with 5' to 6' agaves may weigh three or four times the original weight.
Wind resistant can be another important factor with large plants on a rooftop, especially in hurricane impacted areas.
When you increase a roof's live load fourfold you may cause structural failure issues.
Treat some succulents as potential large shrubs or small trees. Remember, just because a small succulent looks just right for your green roof doesn't mean it will stay that way.