Green Roofs: Mainstream and the Industry

August 3, 2012 at 5:04 pm

Anyone working on green roofs outside of Europe probably has the impression that green roofs are mainstream back in the Motherland (i.e., central Europe, where green roof systems were developed in the late 1970s).  That a green roof professional in Germany or Switzerland never has to answer that ever-popular question, “What’s a green roof and what’s it for?” because everybody either knows what it is, has one of their own, or works in some inter-related industry.

Well, I’d like to set it straight.  In fact, even in the Green Roof Motherland, where millions of m2 are covered in green roofs, many people have not got a clue what a green roof is or what it’s for.  I’ve been working on a green roof project in Germany the last 3 summers in a row, and have encountered countless individuals who don’t know what to make of my profession when they first hear it.  And it’s not the profession, either, it’s the green roof bit.

I suppose green roofs are hard to see from below, so even a totally vegetated roofscape would remain anonymous.  Only those in the know will notice the typical green roof species growing in the pavement cracks and look up for the affirmative flower heads peeking over the parapet.  And in the case of municipal support mechanisms, green roofs are just one of several solutions for rainwater retention, so not really all that special.  Thus, although widespread, I think it’s safe to say that green roofs still inhabit a small niche within European culture’s radar.

That’s why I find these current Orange Me advertisements so striking.  The Swiss  telecom  provider is using green roofs as the backdrop to their current advertising campaign, both on their website and on placards and posters.

The green roof aspect of the advert is a subtle after-thought, adding simply a tactile basis to imagining what is must be like to play Frisbee above the skyline of a big city. The ad is underscored by the keyword “freedom,” which gives the sense of breezy calmness.  Perhaps the players are high enough above the city that they can actually speak to each other from their respective rooftops?

Perhaps this advertising campaign will put an end to the “what is”¦” questions and guesses of function and intent.  Hah, just wait, in the near future we’ll start getting comments like, “Oh, do you mean grass roofs like the ones meant for highrise recreation?”

Hard facts: green roof markets are still growing

My observations above, of interacting with Europeans about their green roof awareness, are clearly rooted in the present and near-past.  This advertising campaign must, in fact, be a sign of the future, namely one where green roofs really have arrived to mainstream awareness.  Recent reports from two green roof industry associations suggest this may be true.

In Germany, the green roof industry association FBB (Fachvereinigung Bauwerksbegrünung e.V.) recently surveyed its membership and reports that the green roof market grew by around 19% between 2008 and 2011, with extensive green roofs holding 87% of that area (calculated according to m2).

See Figure 1 below for the % proportion by intensive and extensive green roofs per year.  The FBB estimates that 8 to 10 million m2 green roofs are installed per year in Germany.  Not bad for a market that was established over 20 years ago.

Figure 1

Across the pond, Green Roofs for Healthy Cities (GRHC) reports an increase by 115% (in m2 coverage) over last year, suggesting an “era of triple digit growth” by its corporate membership’s reported activities.

The North American green roof industry association identified the top 10 metropolitan regions for square footage installed in 2011 and found that Washington DC has overtaken Chicago (for that year, not total are greened), which had always held the lead since the survey began in 2004.

Figure 2

(Caveat: Remember that the annual GRHC survey is only sent out to its corporate membership, missing out on numerous companies, government entities and the like.  Of course, it is a great market indicator, nonetheless.)

In any case, are green roofs completely mainstream?  Unfortunately, not yet.  Is the market growing?  You bet!  Hopefully green roofs will continue to populate various advertising channels and further enter the collective subconscious of the world’s consumers.

~ Christine

Chic Sustainability Watch: Trends, Projects & People – Disappearing Acts

April 2, 2012 at 3:44 pm

As a green roof designer and advocate, I am constantly searching for examples of projects that highlight the aesthetic potential of green roofs and feature vegetation as the primary driver for the building design as a whole.  One of my greatest frustrations is the lack of imagination and creativity displayed in so many of today’s extensive green roof projects.  Yes, a simple sedum carpet will provide the environmental benefits that green roofs are known for, but what a wasted opportunity to create a living, dynamic, piece of art for the building and its occupants!


So it comes as somewhat of a surprise that my topic this month focuses on the camouflaging capacity of green roofs.  Why would I want to celebrate this particular ability when my main goal as a designer is to draw back the curtain on green roofs and fully integrate them into the common parlance of whole building design?  Because sometimes the building and its design are not the primary focus of a project.  Sometimes the site itself is the star attraction, and the buildings placed upon it need to blend into the background and assume a secondary role.

(Image via: Inhabitat)

And this is where green roofs can turn an awkward interloper into an elegant native.  Here are some stunning examples of projects where the inclusion of a green roof transformed a building from an object in the landscape to an object of the landscape.


Frank Lloyd Wright’s Falling Water is an icon of modern architecture.  Nestled into the woods of Bear Run, PA, the house seamlessly blends with the streams and trees of the surrounding landscape.  When Fallingwater Institute announced a competition to create on-site accommodations for the Institute’s educational programs, Patkau Architects of Vancouver rose to the challenge and designed six houses submerged within the Bear Run Nature Reserve.

The houses rise and fall with the hills of the preserve, merging with the meadow prairie grasses.  Only a few simple doors and windows peek out from the hillside; the rest is covered with vegetation.   As stated by the jury, “We feel that the winning design by Patkau Architects will allow Fallingwater to grow by actively demonstrating the principles we espouse: good design in harmony with nature.”

(Images via: Dezeen)


When clients learned that they could develop a mountain site adjacent to the famous thermal baths in Vals, Switzerland, they turned to the Dutch architecture firm, SeARCH.  The holiday residence peaks out of the alpine hillside, its main entrance an old Graubünder barn.  An underground tunnel leads to the focal point of the house, a large central patio carved out of the hillside, framing views of the Alps and allowing light to stream through to the underground rooms.

(Image by Iwan Baan via: Arch Daily)

From the architect’s description of the site: “The local authority’s well intentioned caution, that unusual modern proposals were generally not favoured, proved unfounded. The planners were pleased that the proposal did not appear “˜residential’ or impose on the adjacent bath building. The scheme was not perceived as a typical structure but rather an example of pragmatic unobtrusive development in a sensitive location.”

(Images by Iwan Baan via: Muuuz)


Östberget is a hill in the center of the northern city of Östersund, Sweden that provides magnificent views over the city and its adjoining Great Lake.  The hill has remained relatively undeveloped, despite several tourist-centric proposals to the contrary.  The design for an earth sheltered restaurant, an elevated walkway, wind-driven lights, and rest areas on the site arose from a discussion between architect Johan Berglund of London studio 42 Architects and Färgfabriken Art Space, an art institution and gallery in Stockholm.

(Images via: World Architecture News)

Their goal was to present Östberget as more than a site for skiing and winter recreation; to create a modern identity for the hill and its town that included “the potential to create a place for all, without having to make big alterations to the natural environment.”  The result was an exhibition to spark debate and inspire enthusiasm about the future of the city of Ostersund.


Scottish architecture studio Groves-Raines Architects has raised the compost shed up from its low-brow roots in the far back corner of the garden and into the realm of high design.  Their elegant shedat Inverleith Terrace in Edinburgh  features a series of intertwining rebar that twists and bends towards a green roof enveloped by grasses.  Like woven willow baskets, the steel rods form organic walls and generate a pattern of dappled light that is continuously shifting.  Air and light entering through the gaps provides ventilation for the compost.

The green roof serves a dual purpose, first to remind visitors of the cyclical nature of composting (the grasses above are fed, no doubt, from the compost created below), and second, to link the shed to its surrounding wooded context.

(Images via: Dezeen, ©  by Dan Farrar)

After looking at these projects, I’m happy to admit that there is a place for subtlety and camouflage within the green roof design cadre.

Until next time,


GPW: Asphof Hen Unit

April 17, 2010 at 10:58 pm

Our Greenroof Project of the Week (GPW) is the rustic extensive 1,000 m ²   “Asphof Hen Unit” greenroof in the beautiful countryside of Rothenfluh, Switzerland.   A conglomeration of seven medieval villages, Rothenfluh is a picturesque municipality in the district of Sissach in the canton of Basel-Country in northern Switzerland.

Aramis and I had the pleasure of visiting the lovely area in September, 2005  where I presented my paper “An International Call for The Greenroof Projects Database” at the first  The World Green Roof Congress held at the University of Basel,  Switzerland.   The Congress was co-organized by ZHAW – Zurich University of Applied Sciences Institute of Environment and Nature Resources, Centre Urban Greening, Competence Centre Green Roofs (Hochschule Wädenswil) – and the  International Green Roof Association (IGRA),  among others,  and the tours were led by graduate students and volunteers from ZHAW/The World Green Roof Congress.

We jumped at the opportunity to join one of the local tours that encompassed “Green Roof Week” from September 12 -17.   Congress attendees had a choice of a wide-ranging excursion program ranging  from one to three-day trips, “showing examples of good practice on famous green roofs in Switzerland and the surrounding area of Basel.”    We opted for a one-day tour and wonderful host and guide was  Nathalie Baumann, MSc / Biogeograph, ZHAW Research Associate, who specializes in the ground-breeding Lapwing bird population nesting atop various brown and greenroofs in the area.

We visited six very different applications, from one of Nathalie’s research sites atop a huge pharmaceutical manufacturer to the largest solar roof installation with greenroofs in Switzerland, to a greenroofed cattle barn and this organic chicken farm with two greenroofed structures, where we enjoyed a fantastic Swiss lunch, too.

The owner, Matthias Eglin, really wanted to tread lightly upon the land in terms of blending the large chicken barn/coop into the landscape and providing  a literally cooler environment for his 2,000 organically-raised chickens.  

He turned to renown biodiversity researcher Dr. Stephan Brenneisen of Hochschule Wädenswil (also the coordinator of the  World Green Roof Congress and president  of the  Green Roof Competence Centre), who served as project consultant for the Canton Basle Rural’s Nature and Countryside Protection Commission – see the federal service project on ZHAW’s website.   Their intent was to establish  an extremely  low maintenance xeric landscape  on top of an agricultural utility building and have it eventually naturalize  to mimic the surrounding terrain.

So in 2002 they constructed the Asphof Hen Unit using inexpensive local materials – so local in fact that they harvested and shred Miscanthus sinensis (China grass/reed) from Mathias’ own property to serve as an inexpensive lower substrate and water retention layer.   They excavated  5 cm of loamy humus topsoil from their former orchard area and used it  as a free growing medium.   The annual Phacelia tanacetifolia (Lacy Phacelia), used extensively in Europe both as a cover crop and as bee forage, was included in the grass  seed to break up the soil mix and act as erosion control.   Other herbs were included in the roof as well.   Here’s the roof, below,  in 2002:

And below, three years later, in 2005:

The  natural temperature control reduces the heat by up to seven degrees in the summer (relative to outside temperatures), due to cooling effects of evaporation, resulting in more stress-free chickens!   When we were there it was fun to watch them roam freely about the property, hopping from one roof to the next.

Getting up to the roof took some care and trust that people were holding the ladder on both ends – and as usual I didn’t have the best shoes on..but it was fun!   And it was very grassy:

The second 1,200 sf greenroof is found on the Hay Shed Greenroof, constructed in 2005,  which shelters hay rolls used on the farm property.

Christine Thuring served as a Congress team member and guide on one of the other tours during the Congress.   Co-founder of Green Roof Safari (and Chlorophyllocity and, of course, one of our contributing editors), along with Jörg Breuning (of Green Roof Service, LLC)  she has lead tours here since, as well.   Green Roof Safari offers special access to the European greenroof industry with custom designed tours with multi-lingual guides specializing in highlighting current and historical trends in policy, research and design for the areas visited.

Christine shared these two photos with me and informed me that the roof continues to be monitored, especially the soil substrate and how it has developed with time – Dr. Brenneisen above with the group, and measuring the roof soil below:

Christine succinctly says of the project:

“The Asphof chicken shed demonstrates innovative, economic, simple success.” ~ Christine Thuring

So successful that they don’t even mow it – the roof meadow acts as a self-sustaining system, fully integrated into the landscape.

If you’re interested in seeing this project, you’re in luck.   Now in its sixth year Ltd will be again partnering with Hochschule Wädenswil for their famous “Swiss Green Roof Tour 2010” which  will be held on May 6-7, 2010.    You’ll not only get  Dr. Stephan Brenneisen, but also the indomitable Dusty Gedge, Director of, both of whom are internationally recognized for their work on greenroofs and biodiversity.   Much of the focus of the tour is how research in Switzerland has developed an approach to green roofing that has biodiversity at the heart of their design.

From roofs designed for lizards, to those that have been designed for rare bees, beetles and spiders, this year the tour includes visits to roofs where Swiss researchers are studying ground nesting birds – and to where chickens are happy, too, on the ground and on the roofs.

~ Linda V.