in the news


Ad: American Hydrotech









Back to Guest Editor Columns

A View from the Sky Trenches

PKC of hadj design & the Northwest EcoBuilding GuildPatrick Carey, GRP, is our Architecture Editor (2005).  He writes an occasional architectural column entitled "A View from the Sky Trenches," where he selects and discusses pertinent greenroof industry topics.

Patrick has a degree in architecture and lives in Seattle, Washington, principal of hadj design, a green roof design-build company.  Patrick is also director of the Northwest EcoBuilding Guild's Green Roof Project.  PKC is also a trainer for the Green Roofs for Healthy Cities Green Roof 101,  201, 301, & 401 Courses.

View Patrick's Profile

How to Survive on Planet Earth:
Changing Our Relationship with the Botanical World
November 30, 2010

We extol the virtues of nature and the botanical world in our work and the work of others we encourage.  What the hell, it’s our business.  If we weren’t pushing plants, we would have to find something else to push.  Any junkie in Needle Park will extol the virtues of the poppy.  Piles of expended Bic lighters under alley fire escapes will attest to the popularity of coca.  Where would Lucrecia Borgia have been were it not for a working knowledge of plant derived poisons?

Poppies; Photo by Rosie Hibbs

Where would ADM and Staley be in their agribusiness ventures were it not for the malleability of corn and soy beans?  Just imagine all those diabetics so thankful for the ubiquitous presence of corn syrup in our prepared food!  The bloodbath we call Juarez is all about plants, and a few other things.  At different times of year many of us suffer from airborne plant products and use other plant products to alleviate the symptoms.

Photo Source: USDA

So, hurray for plants!  I say this not to condemn plants but to illustrate that there is no universal ethic going on here.  As living entities, we are all striving for advantage and increasingly competing for dwindling resources.  The blessing in disguise is that we are mutually dependent.  Now, like no other time in human history, we are in a position to connect dots.

Through the rapid increase in shared data and increasing sophistication of our means of inquiry we can start to see the connections between water use and drought, between slash and burn agriculture and build up of Co2, between ocean temperatures and jet stream variations and changing weather patterns.  We are starting to see how some global functions are better given to the plants and not machine replacements.

Besides the global corporations and the national governments there is the natural world which is becoming a new economic heavy weight on the scene.  The context of environmental goods and services is an economic principle that transcends both capitalism and socialism.

Adam Smith’s Wealth of Nations refers to an economic model that assumes growth based on increasingly advantageous specialization.  It was written at a time when the world appeared to be infinitely abundant, at a time when growth had no limits.  Two hundred and thirty some years later we have found that this is not the case.  As our increasing specializations have revealed, fuel, arable land, and other natural resources can be stressed and even depleted as populations and their per capita needs increase.

Past wars were over oil. Very possibly the next ones will be over water.  Mark Twain had an interesting idea when he said “Whiskey is for drinking.  Water is for fighting over.”  We are beginning to discover the limits of technological solutions in that they too frequently assume the same infinite abundance that Mr. Smith did.

There are those who would say that we have nurtured a belief in the afterlife because we cannot bear to accept the finality of death.  There are those who have clung to the belief that a sacred text endows man with the care taking responsibilities of our earth. Unfortunately, the owner’s manual was not provided.

Left: São Paulo, Brazil; Right: New York City, NY, USA

There are those who have nurtured a belief in growth because we cannot bear to accept restraint. This is Smith’s Achilles Heel.  After a long history of capital accumulation in pursuit of this illusion you can imagine how difficult it is to steer this Titanic away from the iceberg.  It is the very self-interest that is the bedrock of Smith’s theory that is its undoing.  It is blind to the likelihood that we, along with other natural forces, have set into motion the engine of our own extinction.  The iceberg cometh.

Flawed but beautiful, and poetic in its irony.

To me plants are like next door neighbors who invite you to their BBQ, but whose teenage son might slit your tires, the productive co-worker who is a racist but keeps it outside the work place, or the too friendly acquaintance you try to keep at bay.  We strike Faustian bargains with our botanical brethren, and they with us.  Bargains not unlike the ones we struck with the Cherokee.

A look at a possible scenario -
Sequence 1:  An unpleasant aftermath.

We know too little about the natural world to realistically consider ourselves to be enlightened.  We have not fully shared.  So now there are stark disparities that fuel highly focused myopias like fundamentalism, reformulations of imperialism, and defensive reformulations of our histories and even the nature of the world.

Sequence 2: Earth healing itself.

“Hey!  Mr. Mouth!  What the hell does this have to do with green roofs?” you say.  My reply is that we should not expect our approach to green roofs and living walls to be any less flawed than our past approaches to anything else.  For instance, if we need a living building element to perform certain functions our Faustian bargain is that we have to acknowledge it is alive and not some inert building part.  This is a problem I call “The Bauhaus Syndrome.”  It is the conviction that one can construct our built environment out of Legos that can be manufactured with cheap labor and uniformly distributed anywhere on earth for use.

For instance, if we truly believe that green roofs are good for us, and not just a reason to increase market share of our product or service, we should determine where the roof surface is and pursue a strategy to cover it.  This is not being done.

Au contraire, green roofs are most likely put on buildings that represent less than 1/5th of the roof surface.  Why?  Because it is looked upon as an extension of existing business models and not as a particularly green solution.  It is a way of selling more of what we already were selling, only with a green twist because green sells.

We produce research based on what research can be funded.  So, when a particular research topic becomes hot (fundable) an inordinate number of research papers come out on the subject. An example of this is the plethora of storm water retention research that has come out in the past 10 years.  The publications serve to keep some academics employed.  For some, it starts further publications and book tours.  This becomes a closed circle when other, competing; research information becomes available - anecdotal research dealing with unfunded topics.

For instance, design professionals who need to expand their reputations by claiming design credit for projects they did not design.  By “design” here I mean the selection and placement of all green roof or living wall elements.  Once a project has been properly publicized it is frequently forgotten by the designer of record and left to the maintenance staff to either correct the designer’s mistakes or left to evolve on its own.  The “designer” of a green roof who relies on a single source provider is like the car purchaser who claims to be an auto mechanic, yet design credit is usually most zealously guarded by those with the least understanding of waterproof membranes, geotextiles performance, growth media composition, botany, and maintenance requirements.

Sequence 3: She's almost there.

Some green roof design books have been authored by people who have never designed a green roof.  Arranging “where the plants go” is a very small part of this design process.  Yet this aspect gets the biggest attention because it is the most obvious.

One prism we can apply to history is our relationship with plants and landscape.  We scraped away topsoil for high impact development, drilled wells, redirected watercourses, and started incinerating fuels.  After a time we got dope-slapped into seeing at least some of what we had done and also seeing some possible solutions that could be provided by plants.  Neighborhood garden plots, urban reforestation, green roofs, living walls - both exterior and interior - all started to contribute to the replanting of the built environment.

Sequence 4: The natural environment is reclaimed.

There is a media series that speculates what will happen on earth after man’s departure.  We get inklings of this from viewing overgrown Mayan, Aztec, Buddhist, temples and monuments.  The plants return.  Like barbarians at the gates of Rome they stand triumphant in their “chaos” before our “ordered environment.”  We have the hubris to place them lower than us on the phylum scale.  But, after all, it is OUR phylum scale.  In introducing serious vegetation back into the build environment as a partner instead of a servant, we must learn to follow as well as lead.  Too few of us have tried to do this.

Buddhist ruin returning to Nature.

The idea I am laboring at is the need to create some distance between our individual needs for revenue, fame, quick solutions, etc., and to pay attention. We are flawed in so many ways. Our understanding is insufficiently informed. Our logic is easily corrupted by our needs, desires, and weaknesses. Our psychological needs are many times too complex or opaque to analyze.

To reach a point of harmony with our environment – the idea of “green” right? - will require us to step down and back from our “Sheppard” status or “top of the phylum scale” status and get down there with our botanical neighbors who we currently treat like vassals or worse. This is a huge evolutionary step to take for us. We are still at the point where we cannot tell the difference between religion and science.

Some designers have gotten it right and design with nature, not just on it; Photo courtesy of Emilio Ambasz, by Hiromi Watanabe.

Steven Hawking just came out with a book that suggests that God did not create the universe. This is getting flack from a few quarters. I find it ironic that ancient religious shrines and temples are overgrown with plants, their walls gradually being opened by protruding roots, their images being obscured by foliage reaching for water and light.

It tells me we have a very long way to go in a world whose extinction we are hastening.

The natural world is a survivor, and the plants will return.

Patrick Carey, principal of hadj design

Patrick Carey, GRP, has a degree in architecture and lives in Seattle, WA, and also has backgrounds in Philosophy and Professional Theatre.  Director of the Northwest EcoBuilding Guild's Green Roof Project since 2000, Patrick is also principal of hadj design, a green roof design-build company.  hadj has designed and installed over 75 green roofs that range in size from chicken coops to complete houses to commercial installations.  hadj design has pioneered the cross-training of its crews in all aspects of green roof installation and has taken on the challenge of getting green roofs of all scales up and running.

Patrick is also a trainer for the Green Roofs for Healthy Cities Green Roof 101,  201, 301, & 401 Courses.

Contact Patrick at

The Minions Project: A Bio-Regional Greenroof Research Call
November 2007

By Patrick Carey

I have never ceased to be surprised at the ingenuity and zeal of people determined to discover a solution to a problem.  With green roofs, living walls, and other biophilic building elements, some of the biggest challenges are the collecting and analyzing of data.  Every approach has its shortcomings.  If a manufacturer of a product or provider of a service offers research data, there is always the possibility of conflict of interest.  If an academic institution offers research data, the implications of the results may be highly limited to the micro-climates of the test apparatus.  If a layman does research, there is always the possibility of lack of scientific rigor in designing the experiment, collecting the data, and analyzing it.

On a recent trip to complete a green roof project I was told there were several others in the area.  I ran into 25.  Some were on sheds.  Some were on houses.  Some were on barns.  And I don't think a single one of them made it to a design magazine, was studied for its behavior, or even listed on any web site.  (Publisher's Note:  The Greenroof Projects Database, a free international online resource, lists projects of all shapes and sizes, so submit away!)  I also have run into people who want to put up a test green roof in order to evaluate its performance, but are not members of a study or academic institution.  My point is that there is a rich source of information out there and plenty of people willing to get it.

So, I came up with the idea of the "Minions Project."  The minions are those who follow up on the ground-breaking, earth shattering, Nobel Prize winning achievements of primary researchers and replicate their work in other bio-regions, this making it more useful information.  This is much less glamorous work, but, in my opinion, equally valuable.

How do we pay for it?  However we can.  The point is to not use grant funding as a necessary condition to do the work.  This is where the academic researchers frequently get held up.  Ben Franklin, Edison, and Da Vinci rarely used grants as the necessary starting point for their work.

The caveat is that contributors must subject themselves to scientific rigor.  Partnering up with local schools or NGO's is a great idea.  Perhaps in your locale you can enlist the help of government sources, labor, and materials suppliers.  Perhaps you can establish a dialog with researchers in the field and in the academy for guidelines on procedure and analysis.  Leave your ego at the door of the lab or test site and go about the work as a search for truth versus a proof that you are right.

The topics?  Any and all.  For example, you have a green roof on your chicken coop.  No you don't, you have a research test panel on your chicken coop!  Here is how you might start out: List the latitude, longitude, and elevation (borrow someone's GPS) of the roof.

What is its slope(s)?  Which direction does it face?  How deep is the media?  How accurately can you define and measure the components of the growth media?  Are there any micro-climatic influences on the roof like shade/leaf drop for a tree, wind patterns, sun or wind blocked or focused by adjacent structures?  Now you know what you have.

Get a two dollar plastic rain gauge and put it in the middle of your green roof and point it straight up.  Collect the rain runoff in a 55 gallon rain barrel and record the water levels of the rain gauge and the barrel at regular intervals.  When either of them is filled up, empty them both (or disconnect the barrel from the downspout) and start again.  This data would not pass muster for a scientific paper.  But, when added to the data of others, it starts to create a body of evidence that can be substantial.  And, you can always get more precise.  For instance, you can take more readings during rain events and create a graph of roof behavior. You can send water samples to a lab for analysis (call your local municipality for a possible free test).

The beauty of a laboratory is that you can isolate the variables you want to study and see how they behave.  The drawback here is that these same results might not be obtainable in the real world.  The drawback with a do-it-yourselfer researcher is that they can have so many independent variables in their study that any scientific inferences will be weak at best.  But even institutional researchers argue over the proper protocols to use and whose produces better and more useable data.  So, you would not be alone, and there is strength in numbers!

If you want to fashion an experiment, we should be able to get the help of researchers in the field who might be willing to help with the design of it.  On a smaller scale, there are a number of successful (and very sturdy) tabletop green roof trial gardens out there which we can replicate in any region, and we can give you a materials list and simple details for you to construct.  These can be conventional built-in-place models or modular system tabletop models.   Below are two examples in the metro Atlanta, Georgia, area:

Click to see the Project Profile! Photo Courtesy Janet Faust of JDR Enterprises, Inc.Click to see the Project Profile! Photo by LSV

The JDR Greenroof Demonstration Model & Trial Gardens at North Metro Technical College in Acworth, GA are conventional built-in-place test modules.  Installing the J-DRain GRS in May 2004;
Photo by Janet Faust.

The Greenroof Pavilion & Greenroof Trial Gardens of Rock Mill Park in Alpharetta, GA, have built-in-place test modules (left and out of view)  and a modular system tabletop (right).
Photo by Linda S. Velazquez, October 2007.

Or you can assemble pre-made kits for more realistic structures, such as storage sheds.  For example, build two Tuff-Sheds like the kind sold at Home Depot, as shown below from an installation that the North West EcoBuilding Guild volunteers and I constructed in 2004:

Eco-Shed in Seatlle, WAPhoto by Patrick Carey

Phinney School Ecoroof waiting for the green stuff.  Photo by Linda S. Velazquez, July 2004.

Tuff-Shed retrofit by Northwest EcoBuilding Guild volunteers. Photo by Patrick Carey.

Use the interior space as your storage, but use the pitch area under the roof (the 'crawl space") for testing.  You might be able to borrow some acoustical sensing equipment and see how much sound makes it through the green roof across which frequency ranges, and which don't.  Use one Tuff-Shed as a neutral for comparison - the control roof.  You might even be able to design the roof of your test shed to fit various, moveable assemblies for testing.  All this is relatively cheap and at the same time is potentially useable for other practical, non-research functions.  The issue is rigor.

Experiments that evaluate the organic needs of growth media based on plants, depth and bio-region are still in their infancy. Thermal and acoustical information is still highly specific to particular test facilities.  Depth of media and plant species that work should be replicated by as many people as possible to discover the applicable limits of scientific conclusions.  I would even include the anecdotal types of reports to a certain extent, as a way to target more rigorous experiments.

If this idea interests anyone, I will work to get a coordinated body of information out to the "minions."  This information will be shared by the minions here on until we have enough information to be substantial.  Let's say, we work on projects and come up with a list of potential work between now and March 21, 2008.  Figure we can check in at the equinoxes and solstices, or every fiscal quarter.  This information need not all come from experiments.  I am including a piece below by an independent researcher, Stephan Elliott, of October 19, 2007 who is examining the embodied energy of growth media components; some greenroofs are greener than others.  Stephan’s work helps to focus on part of this issue.

With this Minion Greenroof Project Call for Research, I see a community of academics and independent field researchers getting more information out and with less cost than is now the case.  So, who is up?

~ Patrick Carey
Architecture Editor

Read the research paper "Embodied Energy Comparisons - Light Weight Aggregates and Pumice," by Stephen Elliott of October 19, 2007 here (PDF).

Patrick Carey has a degree in architecture and lives in Seattle, WA, and also has backgrounds in Philosophy and Professional Theatre.  Director of the Northwest EcoBuilding Guild's Green Roof Project since 2000, Patrick is also principal of hadj design, a green roof design-build company.  hadj has designed and installed over 75 green roofs that range in size from chicken coops to complete houses to commercial installations.  hadj design has pioneered the cross-training of its crews in all aspects of green roof installation and has taken on the challenge of getting green roofs of all scales up and running.

Patrick is the Architecture Editor here at and welcomes your comments.  Contact him at or phone:  425.482.9763.

The opinions expressed by our Contributing Editors may not necessarily reflect the beliefs of, and are offered to our readers to simply present individual views and experiences and open a dialogue of further discussion, debate and research.  Enjoy, and if you have a particular comment, please contact the author or send us an email to:

Green Roof Activism or We are All Bozos on This Bus. Firesign Theatre
August 2005

By Patrick Carey
All Photos Courtesy Patrick Carey unless otherwise noted.

On the one hand green roofs are the fastest growing segment of the roofing market.  On the other they are microscopic in terms of public familiarity and widespread use.  We wait.  We wait for the definitive book that will describe exactly how to design and build one that is perfect, tell us exactly how much it will cost, and exactly how it will behave over the 40-60+ year life span. We wait for the studies to come out on storm water, thermal performance, etc.  We wait for our neighbor down the street to get one first.  We wait for enough of them to be built so that we can take tours of all of them and see for ourselves what the pictures and words are all about.  We wait while the Germans and Japanese make it a standard of construction.  We wait while the trades in other countries learn to actually talk to each other.  We wait for the incentive programs and the grants.  We wait to overcome our unspoken fears.

Spontaneous greenroof by Nature

This garage decided not to wait for humans, grants, or incentives - just the perfect set of climatic conditions, etc., and it developed its own green roof. Moss grew spontaneously on this roof -completely the result of neglect.

The implication being that green roofs are going to happen with or without us so we might as well help out the process. Examining these kinds of things closely can teach you a great deal about how green roofs operate.

I can’t help but wonder if there isn’t some psycho-pathology at work.  This roofing approach has been around since ancient Iraq.  The modern evolution of it has been around since the late 1970’s.  At some mysterious point enough adventurous people will just spontaneously start building green roofs and that will be the beginning of the sea of change.  This hasn’t happened yet.

But there are signs.  D.C. Greenworks in Washington, D.C., Northwest EcoBuilding Guild in Seattle, Ecoroofs Everywhere in Portland, OR, and other experimenters and advocates in Chicago, Minneapolis, New York, Vancouver, B.C., and Austin, Texas are throwing up green roofs.  Some leak, some have all the plants die, some work beautifully, some would make a green roof designer cringe or a roofer shake his/her head.  But they are going up.  When they screw up, the next ones are better.  When they work, they are replicated. When there is no money, they make them small.  When there is money, they get larger.

It’s all happening now and accelerating.  So here are some examples and ideas to jump-start a green roof movement in your area.  You might look at it this way: how bad a failure can you tolerate?  And then operate within those limits. I 'm not talking about installing your home or business with a green roof on the first go.  Start small and go from there.

Example # 1: Tom Liptan in Portland, Oregon, now known to very many people as a green roof resource and advocate, shoveled some backyard dirt on his garage metal roof over a sheet of visqueen, threw some seeds on it, watered it and then measured and observed it over a 9 year period.  No cost, no grant, no public incentive, not even a particularly great design.  But from that experiment sprung a green roof movement in Portland.

Photo Courtesy Tom Liptan, ASLA

See Tom Liptan's Garage in The Greenroof Projects Database

Example #2: Jon Alexander, a member of the NW EcoBuilding Guild in Seattle, volunteered an old garage.  A bunch of fellow members volunteered to do some research on the net.  They got a few donations of free materials from companies who either wanted to get some cheap market development or advertising, and they gave it a shot.  Now they have 20 green roofs up and running on structures from chicken coops to complete single-family residences.

Greenroof in flower in July, 2004

The Alexander garage. Photo by LSV.
Publisher's Note:
Read more about the NW EcoBuilding Guild in Patrick's 2003 Guest Feature Article here. Read about Seattle greenroof activity in Linda's Aug/Sep 2004 Sky Gardens column here.

Example #3: In Chicago, with a mayor touting the benefits of green roofs, a small group started exploring the possibility of green roofs by starting out with models shown to some landscape people, and then built some small structures with green roofs.

Example #4: In Victoria, British Columbia two fellows with dreams of a small landscape business attended a green roof conference in Portland, worked with a green roof design/build business for a few projects, and helped them with a few workshops.  Adam Weir and Liam Hall of Paradise CityScapes took what they learned to design and build small greenroofs on accessory structures in Victoria.

Cathouse greenroof training

Doghouse greenroof training

Left: Adam Weir and Liam Hall starting out a multi-level cathouse with green roof. Right: Josh Powers demonstrating EPDM membrane application for a doghouse.

Example #5: In our nation's capitol, D.C. Greenworks uses training on green roofs and other activities as a way to help people get job skills.  Because greenroofs involve a wide variety of skills form landscaping to carpentry to roofing to metal work, to (and this is the important part) making them all work together, trainees come out of this program with a wide range of skills.  As they work in the community, they bring with them the skill and understanding of green roofs that private house project people tap into.

Read about 1425 K Street above in The Greenroof Projects Database. Photo Courtesy D.C Greenworks.  Publisher's Note: Read about D.C Greenworks in director Dawn Gifford's August 2003 Guest Feature Article here.

Example #6: In Austin, Texas, a homeowner read about green roofs and thought he might try one on his property. Auten imitated the scrub pine and cactus landscape surrounding his house, made a small roof and put it at the entrance to his property.

Example #7 Ecoroofs Everywhere in Portland got volunteers together, hooked up with some grants and some skilled roofers and started putting up green roofs. They have about 10 up so far.

Ecoroofs Everywhere came up with this inexpensive drainage detail. One of many ways to drain a green roof. Illustration by Steve Cowden/The Oregonian.  Publisher's Note: Read about Ecoroofs Everywhere in founding member Anthony Roy's November 2003 Guest Feature Article here.  See the Hawthorne Hostel ecoroof above in The Greenroof Projects Database.

There are many examples I have not listed here.  There are design-build classed offered by Colleges and Junior colleges that have taken classes out and built green roofs; classes offering green roof education are common in Japan. A s soon as the right mixture of skill sets is reached and coordinated, a green roof skill-building workshop can take place.  There are more than enough literature and information sources about this subject right now.

Here are some ideas:

Photo by Patrick Carey

Jeff Jaramillo demonstrating TPO technique.

Get on any of the green roof websites (those not selling products or services might be more objective) and study up on assemblies.  Advertise on for free building materials like plywood, pond liner, framing lumber, single ply roofing membrane scraps (or contact local commercial roofing companies or go to commercial roofing construction sites).  I had a friend who would always counsel me on “ the best “ stereo equipment, another example of the high-tech world of computer software/hardware, cell phones and services.  His theory was to wait because some really huge improvement was just around the corner.  His passion to get the ultra-first of its kind-prototype-future-advanced-totally up-to-date thing prevented him from actually getting anything and then moving on from there. I f anyone puts aside 30 days and reads the four major publications on green roofs, the three CD’s of the past three Green Roof conferences in the U.S., and goes through two or three good green roof websites, you will know as much as 90% of all the green roof experts and practitioners around.  Most of the people and companies who promote themselves as experts are expert in usually only one or two aspects of a green roof and leave the rest to consultants they hire.

Learn by doing small projects!

Student trying her hand at EPDM membrane application.

MAKE FRIENDS WITH A ROOFER! (Someone who is familiar with single ply membranes.)  They do not have to know a plant from a car.  If you can’t, then get a single piece big enough so you don’t have to cut or seam it.  You don’t have to be a non-profit or an institution or anything else just someone who wants to build a green roof.  You can get an old dog house, a bird house, a cat house, anything with a plywood roof and build it up to make a shallow trough and then line it with pond liner from Home Depot, or visqueen.  Next, get few small piles (¼ cubic yard – sized piles) of growth medium ingredients like pumice, lava rock, compost, coco fiber, (experiment and get to about 10% organic to 90% mineral in the mix).  If it works, you can be one of the growing numbers of people who make their recipes secret. Y ou can come up with exotic names like “ Roof Dirt 257.“

Go to a construction site where they are doing foundation work and get some sub-surface drain mat.  Now make a roof with some plywood 2x framing on the edges for a shallow planter, line it with your pond liner, or roofing scraps, lay down the drain mat, fill it about 4-6 inches with your “Roof Dirt 257,“ throw some seeds on it and you have a green roof.  That is it!  Will it be the best green roof, the most advanced, the longer lasting, the only one of its kind? No. It might even leak or fall down.  All the plants might die. “What if it rains too much?”  “What if I don’t have the right plants?”  “What if the stock market crashes again?”  “What happens if the bird flu reaches the U.S.?”  "What happens if the Cubans invade Florida?”  LIGHTEN UP!!!  This will not make you a green roof expert.  But it will put you in the game.  Once you have a few of these up, they will be your teachers.

Photo Courtesy Patrick Carey

Tuff-Shed retrofit by Northwest EcoBuilding Guild volunteers.

Going to a Home Depot or Lowe's or other big box store might get you a donated Tuff-Shed, or other prefabricated small, low liability structure like dog houses, kiddie play houses, bird houses, etc. There are tons of plans for building these things yourself on the web.  Now that you have your act together, map out your city and figure where you can replicate this process so that many different kinds of people get to see them.  What is the worst thing that could happen if you make one and put it in front of City Hall – take a bunch of photos, of course.  How about a homeless encampment?  How about a tool shed for a public garden?  A bus stop?  Anything that can benefit from a roof or a canopy can get a green roof. If you are nervous about the structure, make a small one and replicate it.  Get someone with an official stamp to pass on it.

Monitoring: showing how they work can be of public benefit – think of the educational angle.  All you need is a science class, a playground with a small green roof, a $2.00 rain gauge and a 5-gallon bucket or 55 gallon rain barrel with a closed top attached to a downspout.  You now have a storm water monitoring station.  City and county governments love this type of information because it can set storm water policy.  A college engineering/architecture class doing acoustical tests on it, a local roofers union doing an apprentice training on single ply membrane application, a local horticultural group doing some plant and growth media experiments, and you have a movement.

A simple drainage treatment

Fashioning some drainage.

Green roofing is not rocket science at first.  It is simple as dirt at first.  After your first experience with it the nuances and subtleties will come into play.  But these will be in the form of improvements, not in the form of being able to do it at all.  A defining quality of an activist is to be active.  Sartre spoke of having to destroy the world in order to act in it.  I took him to mean that the point at which one takes action is the like jumping off a diving board.  To act means to ignore all that you know, stop letting the way things are now and the security you feel in they’re never changing in unknown ways; hold back the impulse to create.  The worst thing that can happen is, God forbid, you make a mistake!

Example of what you might hear from a conservative:  "For heaven’s sake! Don’t try this at home!!!" illustrating the hesitancy to experiment on the type of ultra-unsophisticated green roof model prototype that I am talking about.

Photo Courtesy Patrick Carey

A small kiosk built during a workshop.

Now imagine a group of previously green roof-ignorant people who have made the leap.  They tried and failed about 3-4 times.   But the fifth time was a charm and they actually got that green roofed doghouse to look like something.  The skills they learned in carpentry, roofing, horticulture, and green roofing in general now are grounded in the homework they have done with the literature in the field.   Now they are players.  They can ask more insightful questions, the skills they learn are now more sophisticated and focused, the people they go to for help are familiar with their projects.  They do a few presentations to a few groups around the town, explaining green roofs in general and showing the experiments they have done.  All of a sudden somebody wants them to do a workshop at their house and in the process build them a green roof.  They become green roof guerillas and do things like put a 4’ x 8’ green roof panel on the roof of a local office building, a school, and a park.  The more they do, the more they learn, the sharper their skills are honed, etc.  Now they teach others and plan a possible start up business.  Voila!  Green Roof Activism.

Up on the roof

Cooler Chickens

Left: A green roof retrofit on a straw bale structure; Right: A green roofed chicken coop. Egg production was documented as a 23% increase. (This is a lie.)

Some words of good or bad advice, as much as you should summon up courage for tackling the unknown, you should fear yourself as much.  In the 6 years I have been green roofing I have witnessed in some, usually those who are the most distanced from actual green roof projects, a kind of turf mentality.  Those people claim credit for the work of others, claim expertise they do not have, and seek to take advantage of a field that is still new and relatively rare.  They come in all forms, the plant nursery worker who attended one workshop and now knows everything needed to consult on green roofs, the academic who is in love with his or her research technique or theory, the green roof system sales person who is pushing the product of his/her company, the landscape architect who assumes that his/her training alone is all that is needed to claim expertise, the architect who visited the actual site twice – first to introduce the green roof installers to the client and second to photograph the result and is now giving lectures on green roofs as though he/she had done any serious homework, the do-it-yourselfer who has stopped exploring beyond his/her project and figures he/she can now stop learning.  I have seen a lot of attitude-copping, even in the mirror, and I deplore it.  It gets in the way.

There is a kind of greed out there, and green roofs are the next item on the menu.  There is notoriety, publication, media interviews; press coverage, grants and awards given out that can all conspire to force you to miss the point: The roof is the expert, not you.  I would trust people who have both dirt under their fingernails and a well-worn pair of reading glasses over those who appear with various mantles of expertise. THERE ARE NO GREEN ROOF EXPERTS!  There are only those who have a disciplined passion for the subject and those whose appetite for notoriety and future business exceeds their ability and knowledge.

~ Patrick Carey

August Reader Email to the Architecture Editor:
Subject: Green Roof & Snow Load Question

Perhaps you can answer a question raised by a Public Works Director interested in installing a green roof on a municipal highway garage. A green roof reportedly provides an insulating effect. The question: In climates with a heavy snow load, does this mean that snow will not melt as quickly as it might from a black-top roof? Will snow load increase? We would appreciate any help you can provide. Thank you.

Dear Reader:  What causes snow to melt on a roof either heat leaking up through the building assembly, a rise in ambient air temperature above the thawing temperature, or reflected heat from adjacent surfaces, or any of these in combination. If you want to get more exact, a rise in atmospheric pressure, heat from a mechanical system equipment, or the introduction of a black body radiator on the roof would also contribute to this effect. Once snow is on a roof in sufficient depth to be completely white to the sky, it will convert very little light to heat. If the snow becomes dirty, it will convert more light to heat. So, what does this all have to do with a black top roof? As long as the snow is shallow enough to show some of the black of a black top roof to the sky, the black top will absorb light and convert it to heat and possibly melt the snow adjacent to the black areas of the roof. In some conditions, the snow adjacent to the black will melt and then refreeze in the form of ice on a cooler part of the roof. Fluffy, dry snow - because it traps air in pockets - is an insulator. Wet snow - because it has more water which has a specific heat of one - transfers more heat.

As more and more of a green roof is revealed by melting snow or snow that has drifted to thick and shallow areas, there will be some conversion of light to heat with a snow melting effect. It will not be as extreme an effect as would happen with a black roof. So, in this case the snow would last longer. In the case of very low temperatures, a black roof might contribute to more ice on the roof due to more rapid thawing (due to the black body) and then rapid freezing (due to the melt moving to a cooler part of the roof). A Boston winter may well have any of these conditions. The big issue here is not whether one type of roof will melt snow more rapidly, but rather how frequently do various conditions occur, and is that frequency significant? A building with bad insulation will melt more snow than either of these roof types in general. A black roof covered with snow is no longer a black roof. A green roof covered with snow is also a white roof to the sky. Once the sun goes down, the advantage of black body radiation is eliminated.

I realize that this is not a simple answer to your question. However, roof behavior is frequently context-dependent.


If the Only Tool You Have is a Hammer, Every Problem Looks Like a Nail or
Every Tool is a Hammer
July 2005

By Patrick Carey

The marketing of green roofs is on the rise.  One of the elements that fuels this phenomenon is the belief that there is a way to create green roof components that can be shipped to broad markets, thus taking advantage of manufacturing efficiencies.  So we now have sedum blankets manufactured in Japan being shipped to the U.S., pre-grown green roof container boxes of metal or plastic being shipped from the Midwest to the coasts, German drain mats and Swedish EPDM membranes being shipped to the U.S.  The common assumption in all this is that a particular component, sub-system, or system is the “be all” and “end all” of its kind and, hence, worth the trouble and expense of shipping.

International trade is not new.  What is interesting to me is the marriage of biology and manufacturing, of ecology with the sharp-elbowed world of the corporate search for profit, and the belief that a manufacturing process that strives to serve an international market can also supply biological components that are viewed less as elements of a natural environment but more as products of manufacture.

Way back when green roofers were using tarred reeds and melted lead or birch bark and pitch for their waterproof membranes, they looked around near them to find the plant and substrate candidates for the biological component of their assemblies.  Some worked, some didn’t.  And an evolution of thought and experience from experimentation with their local natural resources developed into what we now call green roofs.

When large waterproof membrane companies saw the potential to sell more product with the growing popularity of green roofs, they started to introduce their marketing strategies into this arena as well.  Their products could be manufactured and stored for long periods of time.  Their products could serve a wide array of needs and environmental situations.  One could create a waterproof membrane and geotextile system for tropical, arid, temperate, or polar climates.  One could set up manufacturing plants and a distribution system to more efficiently serve growing markets.  These components, whether drain mats, membranes, root barriers, or separation components, were very convenient for the manufacturing sector to produce.  Manufacturers could subcontract out components of their systems, as is done in many in many other manufacturing processes.  A subcontractor who found that his/her product could also be used, with or without adaptation, for a new market would become very excited.

So drain mats that were originally designed and used for sub-surface foundation applications were now “ green roof system components.”  Professionals and contractors with any remote association with any aspect of green roofing felt emboldened to declare a new expertise, with or without the requisite qualifications.

Small manufacturers complying with the vendor’s specifications produce many components for green roof systems.  Various specialists compete for these contracts and so can change from fiscal cycle to fiscal cycle depending on the bidding competition.  This can result in changes in component design, cost, and general ability of those components to integrate with the system for which they are designed.  So, for instance, companies like Tremco, Green Grid, Garland, Firestone, Carlisle, etc., produce green roof systems defined by the manufacturing specialty of the primary corporate owner or product name. What I find interesting about all this is that these companies and more describe their product as a green roof “system” while actually they are principally selling one component, whether that is a membrane or a planter box, or some other single product of a manufacturing process.  I fear that the elements that actually make a waterproof membrane roof a green roof, specifically the growth media and plants, are getting the short end of the stick.

Let us assume that a green roof is defined by the whole assembly of elements that go from a deck with the appropriate slope and strength to the mature and balanced ecology of a plant population.  It seems to me that a vendor of such a system should be able to speak with authority on any of these components and not just the one that they manufacture. However, this is generally not the case.

An alternative title to this article might be “If the Only Answer You Can Provide is a Manufactured Component, Every Roof is a Parking Spot for It,” or “ Every Green Roof is Just Your Component.”  By not recognizing the interconnected nature of many of these green roof components, installers have frequently blown it.  For example, the plants of the Oakland Museum intensive roof garden, built in the 1960's, failed as the medium was designed using nursery trade assumptions, and not designed for long term use.  Little medium components remained in the mix after a few years except fine sand; the organics washed out or blew away.  Moisture retention dropped and the plants lost so much volume in the substrate (slumping) that aeration and drainage were severely affected.  Other elements deteriorated to create plugged drainage.  This is a good example of a failure because it covers several mistakes, bad growth media composition and the flawed theory that created it as well as filtration materials that deteriorated and led to drainage problems.

As wonderful as the Gap headquarters was as an idea and as much applause as it received, the majority of the plants on it still died.  After the Seattle Justice Center green roof became a beacon for green roof enthusiasts, the plants had to be replaced, twice.  At Seattle’s King County Airport the plants got in trouble as well – possibly because the landscape architect specified potting soil as a growth medium. After Portland’s EcoTrust Building’s green roof helped establish Portland as one of the leaders in the green roof race, it developed a sick plant syndrome where the drought tolerant plants started to drown and the water tolerant plants started to starve for lack of water.

For example, architects frequently specify a slope that is the same slope that they always specify for “flat” roofs (around ¼”: 1’-0” or 2%) and therefore, insufficient drainage is generated because the architects didn’t talk to the plant people - who, of course, were never contacted by the “system” provider because the “system” provider makes their money from membrane or drainage sales, not plant sales.  This same scenario can be generated for any green roof system that is simply composed of a bunch of separate manufacturing units whose providers are in poor communication with each other and lack understanding of the interrelationships of all the components.  The component manufacturer with the deepest pockets dictates the system; in most cases this is the waterproof membrane manufacturer.

Manufactures of systems like the ones I’ve mentioned would, of course, point to those elements they manufacture and say how well they kept water out of the building.  Clients of these manufacturers would return for more business, despite the failure of the green roof system, because the manufacturer emphasized the benefits of their manufactured elements.  However, the green roof still failed and would most likely fail again without an in-depth review of the green roof design as a whole living system.

The issue here has to do with the inherently corrupting influence of justifying large inventory expenditure. Once a company commits to the tooling up, manufacture, and stocking of their particular “ hammer “ or solution to the green roof design problem, their investment is then a self-justifying solution.  The investors and those responsible to them must then commit to that inventory and the decisions that lead to it or else face losses.  So we wind up with solutions that are championed, not necessarily because they are the best or most appropriate, but because there is so much riding on their success.

The real faith should be placed not on the inventory but on the intelligence of the decisions.  Intelligence, however, is not a marketable quantity.  A green roof system is difficult to duplicate on a mass scale as it is usually regionally or project-specific. It is a tool that does not fit in a tool chest.

Most honest adults will admit that their learning curve flattens out once they have to start generating money, profit, or revenue.  Green roofs are still a niche market. Because of that no one is yet ready to lay heavy bets on it. It might be a fad. No earth-shattering profits have been realized yet. The subject is too inter-disciplinary for a boilerplate solution for all customers for all regions. In my opinion, no system has been designed and manufactured yet that is worth copying. In this climate, money is cautious. In this climate that still shows so much promise, there is a hunger for a silver bullet, or …a hammer.

I fear the green roof movement will get a black eye for the rushed and failed attempts to grab headlines and the market’s imagination.  For now, failures from the living and natural components of projects like the GAP Headquarters building, the King County Airport, the Seattle Justice Center, the Eco-Trust Building, and the Oakland Museum will be relegated to the same status as the retraction page of a newspaper.  But if a critical body of failures develops, then it becomes a story in its own right.  If this happens, the bright promise of green roofs to provide so many benefits to our quality of life may produce a dismissive response from the market and those who shape it.  And it might take much longer to recover than a poorly chosen plant in a bad growth medium on a slope that is too flat.

So let’s make sure that we design holistically as an integrated inter-disciplinary green roof design team who actually interact with each other, perhaps by using as our tutors the very ecosystems, we in our hubris, claim to master.

~ Patrick Carey

Guest Feature and A View from the Sky Trenches Inaugural Column, April 2005

At Night All Cows are Black or In the Land of the Blind the One-Eyed Man is King

An introduction to the upcoming architectural column "A View from the Sky Trenches," 
By Patrick Carey

Both of these titles allude to the current states of flux within the green roof world, competing theories, phony experts, lack of good public education, and cultural conflicts of various kinds that impede clear thought and progressive action.  Every month we will try to tackle an issue we think is central to the spread of green roofs, and the first topic to be discussed next month will be residential/commercial.  Commentary, adverse or complimentary, is welcomed.

Who am I?  I promote the idea of green roofs as well as design and install them.  My green roof philosophy is that they represent an ecological model that should be reflected in the methods and organization required to realize them.  By that I mean that the roofers have to be comfortable with horticulture and the horticulturists must be comfortable with roofing.  Green roofs should be the result of an interdisciplinary approach, not a result of a series of specialists who never talk to each other.  The best green roofs are not the result of one specialist with a lot of expertise, back inventory of product to move, or business agreement with a few other element producers.

The best green roofs are a result of the breaking down of knowledge and skill barriers, of market share greed, and of outmoded thought and methodology.  There are no green roof experts.  Those who claim this mantle are either misguided or frauds.  However, those who are humble and passionate enough can make wonderful things happen at the border between building and sky.  By showing success in this approach, other barriers to enlightened design and construction can be called into question, and perhaps even remove barriers to leading lives in balance with all of our neighbors, human and non-human.

Six years ago I knew nothing about green roofs.  Thanks to web sites like this I was able to start researching without the market driven perspectives of sales representatives of various products.  I started where I could, doing Google searches, doing library journal searches, setting up email correspondence, and acquiring as much free technical and product information I could from any company that remotely related to the design and installation of green roofs.

With the help of research committees within the Northwest EcoBuilding Guild we compiled boxes and boxes of documents and samples.  (Publisher's note:  Please read more about  Patrick and the Northwest EcoBuilding Guild here.)  Not being certified roofing applicators or a vendor of a warranted product, we asked for Guild members to offer their roofs to us for experimentation while waving the warranty considerations. The Guild is composed of building contractors, architects, engineers, permaculturists, and others new or in the construction industry and trades.  Drawing from their experience we started our first experiments.  First we started to mimic commercial systems.  Later we broke free and started mixing and matching green roof elements, exploring different growth media, plant types, etc.  Twenty roofs later we have a body of research and field experience that gave us the confidence to feel semi-literate about green roofs as a subject of discussion.  What sets this effort apart is that it did not originate with an industry like the waterproof membrane, geotextile, or horticultural industries, finding another market for its respective product in green roofs.  We started with the ecological impulse from the beginning.

The advantage of this approach is that it liberated us from concerns about moving inventory of product that was not originally designed for green roofs.  We came to the perspective that, like our habit of sending cars overseas with the steering wheels on the wrong side or - God forbid,  going metric - our industrial sector is focused less on the specific needs of a new market than moving product and increasing market share.  One of the best ways we had of gathering information was to get manufacturers to talk about the competition's product.  If a green roof system vendor was originally a waterproof membrane manufacturer, we would skip questions about membranes and ask them questions about soil structure or soil biology or plant adaptability to test how into green roofs they really were or if they were just trying to "sell more steak knives."

We found that academics also can suffer from myopia and produce work that is divorced from the interdisciplinary culture of ecology.  So, we proceeded with a skeptical perspective so we could stay closer to what we deemed the truth.  Even after six years and 30 roofs later, I still find myself humbled by the knowledge base and expertise of vendors, academics, and trades-men in the field. The bargain I try to make with myself is that I should never try to take myself as seriously as the least serious "expert" on green roofs.

If you catch me screwing up, let me know.  This column is intended to be an inquiry into the green roof industry and practices.  My perspective is one of many.  So let's put on our clown noses and inflatable shoes and dive right in.  The worst thing that can happen is that I can be mistaken.  In which case someone, I am sure, will enlighten me and we will all be better off.

~ Patrick Carey

The opinions expressed by our Guest Feature writers and editors may not necessarily reflect the beliefs of, and are offered to our readers to simply present individual views and experiences and open a dialogue of further discussion, debate and research.  Enjoy, and if you have a particular comment, please contact the author or send us an email to:


Back to Top