How Hot Do Green Roof Plants Get? Green Roof Plants For Florida and the Southeast

We are seeing 150 degree F leaf surface temperatures this week in Jacksonville.  You need a plant with a low leaf stomata to leaf surface area ration to survive these temperatures.

Green Roof Planting Media - Second and Third Generation Products

After literally thousands of soil mixture experiments we are making strong headway in developing the green roof soil medium that has the qualities we are looking for. As we look back over the years we can readily see how far we have come.

We've addressed the drainage and the flammability and the dust and the compactability and the water retention and the nutrients/organics issues.

Erosion was a huge issue that we wanted to resolve. Our focus was on lightweight, thin (low profile - primarily because of Florida's hurricane propensity), inexpensive vegetated roofs that would not only work on flat roofs AND we wanted our roofs to work on slopes - even severe slopes!

Today I installed a 20SF vegetated panel on a vertical wall at the house, less than ten minutes after the engineered soil and plants had been applied. Wow. We have come a long ways.

But we have a long ways to go.

Now that flexible vertical vegetated panels - less than 1" thick are a reality - now we are looking at technology that will allow us to apply vegetated panels directly overhead on ceilings. So here is the next challenge.

The era of filling planters or trays with dirt, loose soil mixtures, LECA or expanded clay and placing them on the roof is disappearing. Like the dinosaurs these applications will hang around for a while, with good usefullnes with large heftily
-engineered structures. LECA and Expanded Clay may soon be against building code in Florida for use on roofs - imagine a truck bed load of LECA pellets fling through the air in 150 MPH winds - something like a shotgun blast.

Toxicity free engineered planting media will be a requirement. LC 50 testing with minnows will become standard. Green building requirements will affect planting media design too.

The challenges are here - so are the opportunities...

Happy Green Roofing! Kevin

Green Roofs use of Expanded Clay and Lightweight Expanded Clay Aggregate

The State of Florida has recently requested studies analyzing the use of gravel and aggregate on roofs and the potential of gravel ballast to break windows and other fenestration components of a building during hurricanes.

Preliminary research by the University of Florida shows that gravel ballast may be the cause of unnecessary glass failure and subsequent water damage.

Hurricane Alicia in 1983 devastated the Houston area, and much of the urban fenestration damage was attributed to gravel ballast ripped off the roofs by the hurricane force winds and shot across the city like pellets.

As Florida's green roofing industry develops, designers should be aware of the potential for tort damage liability once their specified product damages anothers property.

We should be careful about placing any gravel or pellet like material in a green roof until all the appropriate studies have been conducted to determine the level of safety for such product use.