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November 2008
guest feature article

Modern Green Roof Technology Literally Shipped from Germany!

The Lawn Club on Celebrity Solstice.

By Jörg Breuning, Green Roof Expert and Consultant
November 24, 2008

Photos Courtesy Jörg Breuning, unless otherwise noted.

More than 10 years ago Maryland based Green Roof Service LLC started to educate Americans about modern green roof technology and today many key players in the market rely on my partner, Peter Philippi's, and my experience.  I believe we are the link between the continents as we provide the knowledge which helps America get up to the same knowledge level of advanced green roof technology as found in Germany.

What a view of Port Everglades from The Lawn Club on Celebrity Solstice!

Green Roof Service LLC’s latest project pushes the limits even further and arguably, I believe it will be the most interesting project in the world!  In September, 2008, we installed 15,000 sf of green roof on the cruise ship Celebrity Solstice at Meyer Werft (Ship Yard), in Germany.  We literally shipped a green roof from Germany to the U.S., and soon it will sail all across the world.  After 10 days of sea trials and nearly two weeks of harsh weather on the successful Atlantic crossing to Port Everglades, Florida, we just got back from the inaugural cruise of the Solstice after sailing three days in the Bahamas.

The Vision of the Lawn Club on Celebrity Solstice; Graphics Courtesy of Celebrity Cruises.

When Celebrity Solstice launches in December, 2008, vacationers will find that the grass really is greener on a Celebrity Cruises vacation.  The ship will present an industry first on the top deck of the ship: real, growing grass, set in an innovative new country club environment known as “The Lawn Club.”  The Lawn Club on Celebrity Solstice invites guests to enjoy bocce, croquet and picnic with wine and cheese.  “Feel the grass between your toes or practice your putting,” promises the advertising of Celebrity Cruises.

Ship Facts

Occupancy: 2,850
Tonnage:  122,000
Length: 1,033 ft
Beam: 121 ft
Draught: 27 ft
Cruise Speed: 24 kts
Inaugural Revenue Cruise Date: November 23, 2008

But Let’s Start from the Beginning

In April, 2008, Royal Caribbean Cruise Lines and Celebrity Cruises awarded Green Roof Service LCC the contract to design, engineer, install and maintain a green roof on their largest ship ever built in Germany – the Celebrity Solstice. Under the wing of AMT, Green Roof Service LLC subcontracted the installation to Borchers GmbH Company in Papenburg, Germany.  “We just installed a green roof on an office building at Meyer Werft and now we continue on their ships,” joked Bernhard Mescher, engineer at Borchers Company.

Borchers GmbH Company in Papenburg, Germany with me in the middle.

Richard D. Fain, Chairman of Celebrity Cruises said, “Everything about the Celebrity Cruises brand is authentic. Our vision for a completely genuine experience demanded nothing less than real grass, and we sought out the right innovation to make that vision a reality.”

Realizing the need for authenticity, flexibility and durability in this unusual and highly demanding design, Uwe Harzmann, CEO at Optigreen AG assured, “We are able to modify our components and we will meet all requirements including the FLL Guidelines (German Green Roof Guidelines - Forschungsgesellschaft Landschaftsbau Landschaftsentwicklung e.V).”  The list of requirements had more than 100 items and many things seemed contrary to one another.  See the English FLL page here

Considerations of Sea, Wide Ranging Climates, Fire and Wind Resistance, Stability, and Aesthetics

Here were some of the most important key requirements and considerations for designing a sea-faring green roof:

  • The layer set-up must support the Arctic, Northern Europe, Mediterranean and tropical weather conditions.
  • Fire prevention to meet international marine fire standards.
  • Wind resistant for wind speeds 100 mph and wind gusts over 120 mph.
  • Stable against sliding - ship tilts up to 12° or 27%
  • Highly salt tolerant
  • Environmental friendly materials and run-off behavior.
  • Maximum weight: 130 metric tons.
  • Prime turf grass for activities like Bocce, croquet and golf putting.
  • Resistant for foot traffic.
  • Comprehensive set-up to exchange grass easy and fast.
  • Maintenance program, physically fit and well trained lawn keepers.

The Lawn Club: Left to Right - Peter Philippi, the two lawn keepers, me, and Doc Cisar.

After two years of testing at the University of Florida with Dr. John Cisar on the Celebrity Galaxy cruise ship with a test plot at the Port of Miami and one in Papenburg, the key setup for The Lawn Club was developed and then the grass species were chosen.

Left: Installing subsurface and surface irrigation; Right: The modified drainage layer.

Green Roof Statistics:

  • Type: Intensive with pre grown vegetative grass mats.
  • System: Custom engineered with modified Optigreen AG components.
  • Thickness overall: 5 inches.
  • Drainage layer: 1 ½ inch modified Optigreen FKD 40 Drainage board.
  • Growing media from Germany: Optigreen custom blend with 530 kg/cbm dry and 850kg/cbm saturated weights.
  • 2 dimensional geo grid as reinforcement.
  • Vegetated grass mats: Soil-free turf of Agrostis stolonifera L93, or creeping Bentgrass (a cold season grass).  Mowing Height: 10-15 mm.
  • 4-way irrigation system utilizing:
    • Subsurface trickle irrigation – special piping from Israel;
    • Surface irrigation with water saving sprinklers;
    • Hand watering;
    • Natural rain;
  • 24/7 maintenance by a highly trained golf superintendant from the Philippines.
  • State-of-the-art turf maintenance machines – all rechargeable battery powered.
  • Organic fertilizers and liquid fertilizers for “spoon feeding.”
  • System and components in accordance to FLL guidelines.
  • Roof: welded steel deck with root and chemical resistant coating.
  • 20 cubic meter tank to retain run-off from vegetated area.

Logistical Challenges

When sitting on the Solstice on the grass of The Lawn Club in the Sunset Bar, guests will also enjoy spectacular views in a relaxed atmosphere 120 ft above sea level.  Everything looks nice, green and beautiful and no one could even imagine the construction challenges we encountered along the way.  The Solstice is the largest passenger ship ever built in Germany and keep in mind that the ship yard is 50 miles off shore.  Getting the materials up on deck 15 stories high within a two week time frame from a ship yard where more than 2,500 people and more than 50 contractors were working all at the same time, while hundreds of containers were being loaded sounds like an impossible endeavor, right?  Yet Meyer Werft built the $750 Million Solstice in only 10 months – where time is money and everybody and everything had to work 24/7.

Left: Bringing up the growing media; Right: Spreading the engineered soil mix.

In October, the passage from the ship yard to the North Sea on the dammed-up river Ems was the ship’s first big event.  Hundreds of thousands of people followed the ship by bicycle, on foot, car, camper or boat over 24 hours.  Bridges were rebuilt to widen the passage and the river was dug deeper to make sure no propeller hit the bottom. The 140 metric ton weight of the green roof lowered the Solstice one inch deeper into the water – and although one inch may not sound like a big deal, it was a big challenge for the engineers.

Left: Laying the sod; Right: We're getting there!  A view in the middle of the turf grass installation process.

Sea Trials

Arriving at the North Sea port in Eemshaven, The Netherlands, and now equipped with more materials, the ship was ready to begin sea trials where everything from the ship would undergo extreme tests.  The owner and captain had to prove that  the ship met specifications (high speed, braking tests, incline tests, minimum radius, etc.).  The ship fared well and so did the green roof!

The Celebrity Solstice sailing out to the North Sea, trying the waters and the new ship.

We met all the requirements just one week after installation and here are some trial results:

During the 15° incline test nothing moved – everything stayed in place.  With 100 miles/hour winds along the Norwegian coast, there was not a single failure of the system and even 50 foot waves (with a salt content 10 times more than what people usually put on their breakfast eggs) didn’t have an impact.  We did not experience one single blade of grass damage or with the set-up of the green roof.  Since the temperatures were around 35-55° F, the growth of the grass roots was slow but constant and steady as expected. Helpful was the fact that “cold” water on a ship means around 55-60° F.

Throughout the sea trials the half-acre Lawn Club on Celebrity Solstice performed nicely and without complications; now we were ready for the big crossing over the Atlantic Ocean to Port Everglades, Florida.

A Salty Sea Crossing

Quoting the words of Dan Hanrahan, President and CEO of Celebrity Cruises, “We want our guests to experience the unexpected, like the thrill of sinking a putt on a freshly manicured lawn in the middle of the ocean.”

On the inaugural cruise to the Bahamas.
Left: Putting in the middle of the Atlantic Ocean; Right:
Dan Hanrahan, President and CEO of Celebrity Cruises.

We expected and experienced the unexpected in the middle of our Atlantic crossing – we knew that icebergs were encountered much further north of our route, but our route was also famous for presenting four seasons in one day.  After the first nice day the four seasons were ready to be sampled, and the temperatures dropped close to freezing while the wind was picking up constant speeds of 30-50 miles.

Our current location

Google Earth is a thing of beauty!  Here we are a little more than half way through our ocean crossing at the end of October.

Neither hail nor snow was noted in the log book but on one day a tremendous impact of salt was experienced on the port side of the ship.  Approximately 200g /smtr (1 oz/sf) fell down in clumps from the ship’s awnings and burned holes in the grass over night.  This meant that permanent hand watering of critical areas was part of the daily tasks to save the grass.  Abnormal wind loads and 40% humidity caused wilting of the grass and so the irrigation timer was set to water at maximum levels.  Yet even with the extra water, run-off was hardly measurable.

Left: Canopies over The Lawn Club; Right: Close up right after installation.

With the environmental parameters changing every hour, it truly was a 24/7, full time job monitoring this exceptional project.  For all of us, and especially for Dr. John Cisar, it was a unique, once-in-a-lifetime research experience where we found out that even seemingly small things can have a big effect under extreme conditions.

Left: A side view of The Lawn Club with individuals planters; Right: Here I'm checking on the health of the turf.

While getting closer to Florida, The Lawn Club, which is the central element of the top deck on the Celebrity Solstice, was being challenged from the harsh environment.  Temperatures were increasing and getting over 80° F, and we were having some sleepless nights.  The canopy of the grass needs to be cooled down when getting over 85° F since Agrostis stolonifera is a cold season grass, and so the transition from a cold to a hot climate needed to evolve slowly.  Fortunately, we only had one day with extreme high temperatures and the following days were cooler – which also cooled down everybody’s stress level, too.

Left: Side view; Right: Irrigation controls were set for maximum coverage to ensure survivability.

The Celebrity Solstice embraces many eco-responsible elements and she sets the bar very high when it comes to sustainability.  In addition to the half-acre green roof, here are some other environmentally-friendly features:

  • Entire ship with mostly LED lightning technology saves over 20% of power.
  • Four Hybrid (Common Rail Diesel-Electro) engines.
  • All roofs have photovoltaics (including glass roofs).
  • Advanced biological waste water treatment facility.
  • Recycling and separation of trash and waste.
  • Fresh water production with reused heat and reverse osmosis and low chlorine.
  • Reuse and refining of oil on board.
  • Run-off collection tank only for green roof.
  • Corporate leadership with “Save The Waves” program.

The Lawn Club: Maintaining a passenger lawn area at sea takes a committed staff!

Depending on many issues (climate, foot traffic, etc.) the grass might need to be changed to warm season Bermuda grass.  When?  I don’t know since this has never done before; only time will tell.  The only thing I know is that the system (the layers set-up) will work in every climate, every region and with every type of grass where ever the ship cruises.

On the inaugural cruise to the Bahamas.
Left: Bocce is just one of  the many fun activities to do on the Lawn Club; Right: Croquet, anyone?

We literally demonstrated that modern green roof technology and the German Green Roof Guidelines (FLL) work all around the world – from North to South and West to East.  Rest assured the FLL is a valuable guideline for plantings on impervious areas on Earth (and sea).

Wide open spaces on the open seas on a gorgeous day!

There is no better demonstration of a high quality project than on a mobile green roof traveling the seas of the world.  And we simply delivered what was ordered: Nice, green, and beautiful.

Celebrating the Celebrity Solstice.

Publisher's Note:  See The Lawn Club on Celebrity Solstice in the Greenroof Projects Database with additional designer info and more original graphics.

A nighttime vision of the Lawn Club; Graphic Courtesy of Celebrity Cruises.

The co-founder and co-principal of Green Roof Service LLC, Jörg Breuning has more than a quarter century of experience as a leader in the establishment of the green roof industry in German-spoken Europe, having actively designed, installed, monitored, and perfected his craft since 1980.  Jörg is acknowledged by the German FLL e.V., the FBB/EFB (German/ European Green Roof Association), and the German Landscape Association (GALA-BAU e.V), and his bilingual skills have provided him access to various American associations including the ASTM.

He participated in the largest green roof research endeavor ever undertaken (at Optigrün International AG in Germany, begun in 1994/1995, still ongoing) and has access to the resulting data (not fully translated into English) and an intimate knowledge of the “behind the scenes” circumstances.

Green Roof Service LLC principals Jörg Breuning and Peter Philippi have no allegiance to any specific product manufacturer and they select materials and approaches that work best in any given circumstance.  They preserve this independency and freedom to support a healthy and sustainable development of modern green roof technology in the United States.

Contact Jörg Breuning of Green Roof Service LLC at: 202 Kimary Court 3D, Forest Hill, Maryland, 21050, USA; +1 410-322-8029;; and

The Celebrity Solstice; Photo Courtesy of Celebrity Cruises.

Publisher's Note:

Celebrity Cruises offers comfortably sophisticated, upscale cruise experiences with highly personalized service, exceptional dining, and extraordinary attention to detail.  Celebrity sails in Alaska, Australia/New Zealand, California, Canada/New England, the Caribbean, Europe, Galapagos Islands, Hawaii, the Pacific Coast, Panama Canal and South America.  The line also offers unique land-tour vacations in Alaska, Canada, Europe and Australia through its cruise tour affiliate.  Noted for "The World's Best Large Ships," as voted by the readers of Conde' Nast Traveler (February 2007 Cruise Poll), Celebrity's current fleet will be joined by Celebrity Solstice in 2008, Celebrity Equinox in 2009, Celebrity Eclipse in 2010, and a fourth Solstice-class ship in 2011.  For more information, call your travel agent, dial 1-800-437-3111 or visit  And for more information about Celebrity Solstice, visit

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