Watching Green Roofs in Florida Evolve Over the Years...

It is amazing to watch the plants on a green roof move, find their perfect niche and grow over the years.  The photo here is of a sedum growing down across the roof and into the gutter, then overflowing the gutter and cascading down vertically.  Adding volumetric green to the urban core with Florida Green Roofs! For more information on green roofs, call Kevin Songer at 904-294-2656.

Florida Green Roofs, Roots, Liners, Life Expectancy and Shingles

Yesterday I removed one of the original green, vegetated roofs we had installed in Florida - to replace with different plants - an herb garden type.

I was amazed at how the green roof plant roots had attached themselves to the fabric, creating a strong and binding weave - an important consideration here in Florida's hurricane prone environment.

The shingle roof underneath actually looked newer than the day, years ago that I installed the green roof.

Another example of how green roofs can protect the underlying roof membrane (especially non-irrigated green roofs!)

Kevin

Flat Roofs and Sloped Roofs, Green Roofs for both in Florida

Remember though - the plants you have installed on your green roof generally do not like wet feet, so provide good drainage!

Our field panels have shown that green roof systems in Florida with excellent drainage - nothing to hold the water in the soil - grow the healthiest plants.

Many take the opposite approach and install a water retention layer (material like a sponge - and a good way to grow mold and culture up plant diseases). Though a water retention layer will work when rain events are a week apart - allowing for drying time - the retention layer becomes a detriment during periods of daily rainfall events. All of a sudden the drought tolerant plants are subject to wetland conditions.

Therefore - we have found green roof plants (Extensive Roofs - we do not work with the heavier, more costly intensive roofs) - on sloped roofs do the best.

Moreover, engineered soils will last longer when well drained. Water has a tendency to act as a separation agent (dig down into your backyard and you can tell how high the ground water rises because the water separates organics and inorganics into layers).

Remember - well drained systems last longer and grow healthier plants!

Native Plants and Florida Green Roofs

Every good plant person wants to use native species in their landscape. At least we all confess so anyway. Certainly the term is politically correct and in vogue by most regulatory agencies, municipalities and various conservation groups, native plant societies and NGO's.

I have just concluded several years native plant trials on flat and sloped green roofs - extensive green roofs that are not irrigated or fertilized. I've traveled across the State of Florida to various plant nurseries and native plant nurseries. I've purchased and accepted as free native plants to try on the roofs. We've watched them through 20 degree F weather and then through 150 degrees in the summer. Earlier this year we had an 11 week stretch where we received less than 1/2 inch total rain.

Roofs are a rough, tough place to put plants. Most have little concept of the harsh and unhospitable environment most roofs possess. The winds alone over Florida roofs are desiccating and will dry out most plants in a matter of hours.

Plants with high stomata to leaf surface ratio are doomed on a roof. Plants that cannot tolerate high humidity and sever swings in daily temperatures - 60 degrees F is not unheard of - are also doomed.

But Florida's sandhills and xeric uplands support native species with a promise of being able to tolerate the ultimate test of life on a roof.

Native grasses make it for a season or two, but the constant winds weaken their resistance and ultimately they fall prey to extreme drought or cold. We've looked at the leathery leafed native vines- railroad vine, for instance and again - though it comes back when planted in the ground after a hard freeze - it has not reliably recovered on the roof.

The native Allium canadense - or nodding onion - also shows promise.

Yucca's, such as the native Adam's Needle are strong contenders however they have a tall habit and may outgrow a roof.

Of course there are many South African and European plants that survive and prosper in these conditions. But they are not natives.

So why not irrigate? We have a water shortage and a mold problem in Florida. The first time an irrigated vegetated roof leaks and causes building mold issues, precedent will be set for every other building with vegetated roofs and mold, regardless of a leaking roof or not.

And Florida has a serious water stewardship issue. 50% of all potable water use right now is for irrigation. Good enough reason to not irrigated a vegetated roof.

Many will never be convinced of the irrigation issue - but we are making progress. Native can work. Finding the right species for the right roofs takes time.

The above pictures are of Elliot's Lovegrass on a flat trial panel and Allium canadense on a sloped roof.

Send me your thoughts... & Happy green roofing!

From Drought to Rain - Green Roofing Plants Must Survive Drought and Innundation...

These two photographs depict the difficulty of designing a non-irrigated vegetated roof in Florida. The photo depicting the dried look was taken May 3rd, 2009 after two months of intense heat and no rain. The other was taken June 1st after three weeks of rain. The roof plants have responded well and are now thriving. Happy Green Roofing! Kevin

A Small Herb Garden on the Roof - An Amazing Architect

Rob Overly and his wife Kate want (Kate's direction the roof plants be useful and practical if on the roof) a small green roof Herb Garden above their front door.

The roof is relatively flat and will receive summer sunlight from mid-morning til mid- to late-afternoon.

We will be installing the roof over existing asphalt roll.

Rob rode his Vespa over last week and we planted several trays of seeds - mainly Garlic Chives, one of my favorite Green Roof Plants. Rob is working on Living Machines and other Green Apparati. He is a great resource for Green Building - find him on the web under Rink Design.... You can also track their project at www.robandkatesgreenroof.blogspot.com

Stay in touch for the up to date reports on Rob and Kate's Herb Garden on the Roof!

Propagating Green Roof Plants for Florida Green Roofs

Propagating plants for green roof projects here in Florida is an important component of a successful Florida GR project.

Knowing a plant was raised in the same ecotone where it will ultimately be used is important. This not only secures LEED credits for local material use (and other credits) but it helps in knowing the plant can survive local climatic conditions.

My general rule of thumb is that, here in Florida, a green roof plant should be grown no greater than 150 miles north or south f the project physical location - no general limit on east/west other than the local limits for LEED credit.

The roots shown on the succulent leaf here developed on their own, on a leaf dropped as mother plants were being pruned, a testament to the hardiness of plants. The above pictures also show the importance of saving pruned plant material for propagation - and in doing so being a good steward of resources.

Happy Green Roofing!

Florida Green Roof Project Continues with the addition of more cold tolerant yuccas....

The New Florida Green Roof Project is moving forward! We've added several new cold hardy varieties of Yucca! Stay tuned for more pictures!

Hard Freezes and Florida Green Roofs - Winter (Hard Freezes - one of the many 'H's GRs face in Florida)

Judy and I have been scurrying most every afternoon to cover plants as temperatures have been dropping into the twenties here in Jacksonville. Looking at the Weather Dot Com it appears that around Tallahassee the mercury has hit the low twenties several times. Walking by our green roofs, I look up with frost blanket in my hand and want to climb up and cover the plants. But I don't.

Our green roofs serve as our best trial panels as we've said many times before. I have finally reached the confidence level that allows me to know the plants will survive. Still though, many of the plants on our green roof are hard to find varieties and the cold north winds are desiccating, unrelenting and potentially fatal to humans, animals and plants.

I am always proud the next day to see the plants stand straight and soak up the sun's warmth. Balancing the choice between those plants, like the sedums that can tolerate extreme cold but melt in the fierce pressure cooker like humidity laden summer heat - and the succulents that can take the tropical heat but not the cold has been the key to success.

There are not alot of plants that fit into the category of withstanding both of the above limiting factors. Then you add long periods of drought and long periods of innundation to the model as inputs and the list of plants that will survive shrink even more.

Finally add the requirement the plants must still look good and not be dormant to the above and the list really becomes small....

So as I await days light to see what damage, if any has been done and add the findings to our resource base - I hope the coldest night so far of 2009 will produce the same positive results as those before.

Happy green roofing in Florida!

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 in Florida and Cooler Weather

It is becoming cooler and night now and well should be - it is almost Thanksgiving & most green roof plants on our projects are very happy that the long and tortuous ordeal with Florida's heat and humidity is almost over for a season...

Many of the plants bear battle scars from Tropical Storm Fay (way, way too much water) and the ever present afternoon humidity bath.

The Sempervivums are starting to revive...you can see new growth expanding out from the middle of the plant, the brown, wilted areas falling away from the perimeters.

This is the time of year for dormancy for some of the sedums - - they are turning brown and melting away while others are just melting after a long stressful battle with the Florida humidity.

Iceplant is doing well. Iceplant planted on the ground melted out during T.S. Fay but those clumps on the roofs actually thrived.

Interestingly, the allium likes the cold weather too - its leaf blades perk right up.

So now is a major time for seasonal change in North Florida for green roofs. Stay tuned for more updates!

The New Florida Green Roof project moves forward!!! The Seeds are Sprouting!

It has taken about seven days for the allium seeds to sprout. However they are bursting forth in full force now, even though we are well into the autumn season. Allium is one of my favorite plant Genus'. Allium sp. is a hardy plant - you can find them growing almost anywhere!

Allium's are drought resistant, evergreen and provide significant habitat for all types of wildlife! Watch for more pictures as the plants mature! Be sure to also check out MetroVerde - Judy's website on Green Roofs and Urban Permaculture.

Brown Curly Q's on the Alliums. It has been a while since we've had a rain event...Florida Green Roofs

Other than the tale tell sign that the alliums are aware that it has been a good while since rain has moistened their roof top beds, the MetroVerde Extensive Green Roofs I've been following are looking good.

The Semps have really enjoyed the respite from the humidity and are looking perky and green! Though you do not see them here. I'll post a pic of them tomorrow.

I was out most of the day today taking the International Society of Arboriculture's certified Municipal Arborist exam - I thought it was a hard test - but as I was reviewing the questions, several key phrases jelled in my mind about adding small trees to the MV Extensive roof panels and after consideration all afternoon - I think it will work!!! But of course, as always, we will vet in the field through many tests. Please be sure and stay tuned for more info as the field trials take shape.

Back to the alliums in a second - but first - we are going to develop a spreadsheet for the blog that will allow us to post temperature readings of on deck asphalt, on deck vegetation, below deck asphalt and below deck vegetated sampling points on a set of Jacksonville, Florida roofs. We will keep the readings posted year around for our interests and comments. Right now I am seeing October mid-day below deck under asphalt readings averaging 128 degrees F while below deck under extensive vegetation mats of 81 degrees F.

We are also running LC-50 tests on straight rainwater and then rainwater runoff from an asphalt shingled roof and a vegetated roof. It looks like the only roof that doesn't kill the fathead minnows is...well - we need to wait for the final data.

OK alliums. As you can see in the photo - the alliums are feeling the semi-drought. Though only a trained eye would probably see the stress indication in the leaf blade tips - it is there. But this is how alliums respond to drought. We will keep posting pictures until we experience a decent rainfall event. Never fear for these plants though - they are tough, tough, tough. Judy and I have worked with these plants for years and years. You cannot kill them and when you trim the blades back you can almost see them grow back out!

Can you tell from the photo? Lots of lush green - but look for the thin brown tips. It has been three weeks since a solid rain. If this was a roof with a modular tray system - here in Florida my bets are that you'd have a dead mess. Mat systems are so much better suited for the three Florida H's - Hurricanes, Heat and Humidity...

Until tomorrow! Happy Green Roofing Dreams! Kevin :)

Florida Green Roofs - Prepping the mat with expanded mineral material - perlite, vermiclite, expanded clay, agar, trace minerals, and more!

Episode Three - prepping the planting base - prepping the mat. Lots of standards and regulations, common sense precautions and just plain good BMP's - Best management Practices come into play now that the mat is rolled out. So we've talked to death the reason why we don't like trays and modular systems....Hey I heard of a roofing company somewhere is South Florida who just installed a system of trays on their roof - and the plants died...

But the reason we choose mats is not the reason we don't use trays. The reason we choose mats is because with a mat, the green roof's plant roots can grow as far north, south, east or west they want to grow. No circling (as in trays) and no self strangulation in a couple of years (as in trays).

Sure - maybe Plant A will Run into Plant B. Instead of root circling and strangulation though, the roots will compete with each other and the stronger plant will go onto to survive. The important note here is that there is always coverage - though one may dieback, the stronger or more suited plant survives. The mat advantage has proven itself on the Dearborn, Michigan Ford Motor Company 10 acre roof.

OK - back to the soil...

Wouldn't it be easiest just to fill the mat with dirt from the backyard? - Maybe so - but I wouldn't do it. Think of the weeds, nematodes, fire ants, etc you may be digging up and placing on your roof.

Moreover, ASTM has specifications written for dust and organic matter and more for green roof soil systems. The MetroVerde engineered soil (MV GRP) mixture we use is a proprietary blend - and we add soil goodies to it! I think of it as a stabilized outdoor hydroponic system!

So lay out a piece of plastic sheeting on the ground in an area you won't be walking - please note that if you have outside cats or dogs - they love to use a rolled mat system as a huge litter box! Take precautions!

Roll out your mat on top of the plastic, add the mixture of perlite, vermiculite and expanded clay. Apply the tackifier initial layer. Sow desired seeds or installed pre-grown plugs and reapply tackifier.

We'll explore soil mixtures and tackifier solutions (there are many of these sticky mixtures) in an upcoming post. In the meantime - Happy Green Roofing!!! Kevin

New Florida Green Roof Project - THE MAT !!!!

One of the basic principles of a successful green roof is the base mat. Mats are the preferred green roof base system for Florida Green Roofs - as we have discussed countless times before here. The reason is simple - the roots in plants secured in trays or modular components eventually reach the tray walls and begin to circle around, eventually strangling themselves to death - remember going to the nursery and buying pot or root bound plants - they did not live long....

Welcome to the mat episode...the mat was delivered today! We will unroll it, flatten it out and begin adding the expanded clay, other non-organics and the tackifier (agar based). Sound complicated? Naw.... Watch for the next episode - to be posted later tonight after we do the above tasks! Happy green roofing - - Kevin :)

South Facing Florida Green Roof Project

We will be documenting an approximately 1000 SF green roof project here on the blog - beginning with the initial mat plantings in October 2008.

The mat material is ordered, scheduled for delivery within the week.

The organic seed stock and cuttings are established and ready for installation in the mat system.

Over the course of the next several posting you will view the current roof (asphalt shingles), the liner and liner installation, the mat and mat fabrication and construction and the final product. Feel free to post questions and suggestions! Join us on this project!



Kevin, Jincy and Ruairi

The 3 C’s of Sustainability: Communication, Community Involvement, and Campus Environment," the 3rd Annual Campus & Community Sustainability Conferenc

This conference, held in Orlando will be a premiere event to attend if you are interested in learning the details of Sustainability and Green Roofing in Florida!

Visit The 3 C’s of Sustainability: Communication, Community Involvement, and Campus Environment," the 3rd Annual Campus & Community Sustainability Conference hosted by the University of Central Florida and the Council for Sustainable Florida website for more details.

I will be moderating a panel discussing the Importance of Restoring Green to the Urban Core and will be joined on the panel by Dr. Marty Wanielista, P.E. of UCF, Catherine Burkee of Breaking Ground Construction, and Rob Overly of Rink Architecture. We will focus on the big three benefits of Restoring Green to the Urban Core: 1- Treating Stormwater, 2- Providing a Sense of Place, and 3- Recreating Habitat for Wildlife.

Examples of Dr. Wanielista's Green Roof systems and more will be discussed.

Join us for this fantastic opportunity to look at Green Roofs and More!!!

Living Walls provide the same type vertiscaping - vertical green that vegetated and green roofs provide!!!

Great Reference Website for Urban Heat Island remedies and Florida Green Roofs

Check out this website developed by the EPA about Green Roofs - good basic info...

www.epa.gov/hiri/strategies/greenroofs.html

Florida Green roofs - modular trays or mats? Look out for trays that cause root bound results!

Green roofs are popular now and a huge question I have is with respect to plants developing root binding due to the modular tray walls. I am sure there are many satisfactory answers out there however I am yet to be convinced!

With trays and modular systems - not only will the planting media 'float' out of the tray in a heavy storm event, but the tray walls restrict horizontal growth - and all plants tend to grow outward from their original diameter. Once roots start circling they strangle each other, competing for space.

Mats allow for the roots to grow as far as necessary in any direction. If there is another plant in the way, then competition kicks in and the most aggressive species wins over - however the end result is that the green roof system is always vegetated.

Florida is a tricky climate to use any green roof system in - let alone modular systems or trays. Our climate is totally different than the climate up north and though trays and modular systems may work up north - they are much more difficult to make work in Florida.

Of course - if you want to spend $$$$$$$ on maintenance and design then trays and modular systems can be designed to work acceptably, but why spend the extra dollars when the mat systems will provide the same amount of 'green', put less of a structural load on your roof, and do not require irrigation!

Check out MetroVerde's website - they offer a mat system that has proven itself in Florida - heat, humidity and tropical storms (see the posted video of tropical Storm Fay on Green Roofs)

The two photos here are of sedum center dieback from the plant being root bound, and the actual root circling action. Modular trays are not good for the long tern health of the plants on Florida Green Roofs.