Green Roof Technology Blog

By Kat Harrold

Photo ~ Green Roof Technology

In 1988 fire research testing on green roofs was begun by the Research and Material Testing laboratory of Baden-Wurttemberg in Stuttgart Germany.  Initial testing began with the evaluation of bituminous waterproofing layers.  It was discovered that the bituminous waterproofing when burned produced 50 kWh/m2.  Alternatively when this burn test was done on an extensive green roof with dry grasses only 3 kWh/m2 were produced.  

Tests were then done to see if it was possible to establish a fire that would spread across an extensive green roof and or start a glowing/burning of the growing media.  After several tests the conclusion was made that it was nearly impossible to create a fire on an extensive green roof that would spread across the roof or ignite the growing media.  Conversely it was discovered that a bare regular bituminous waterproofing membrane was 15-20 times more likely to catch fire than an extensive green roof with grasses and perennials.  It is for these reasons that many Germany insurance companies offer a 10-20% discount on fire insurance when a building has a built in place green roof.

By Joe Devoy ~Tellus 360

Photos by Tellus 360

A year has passed since the Tellus 360’s green roof was installed and we caught up with Tellus 360’s owner, Joe Devoy.  We asked Joe to write a few words reflecting on his new urban oasis.

“One day we were standing on our big flat roof, the sun shining down, the wind gently blowing, having a chat.  We were looking at the Marriott and Convention Center being built next door.  Coming up to the roof had become a kind of ritual, a pleasant place to relax and reflect.

When we were on the roof we were still part of the city, but it was a different part of the city. Captured all around us were the sounds of city but we were still removed somehow.  After a few of these trips the decision was made; a green roof must be built on our roof.  We all needed a therapeutic place where city and nature could meet, where the sounds of life relax not excite.

As we talked to Fritz Schroeder of LIVE Green Lancaster and met Jörg and Kat from Green Roof Technology, our vision of a community oasis developed in our mind.  “A better way to live and a better life for our building.”  Our vision for our building has always been for it to be alive, that it could breathe with the city.  We want it to expand and contract, to participate in our life and to help us be better in the way we live.

Our new green roof has achieved that and the life it has brought to our building and our community has been equally amazing.  Now I return each morning for my daily ritual.  The smell of earth and the sounds of a city alive surround me as I enjoy my breakfast from the local farmers market.  I love to hear the city breathe, I love to hear our building breathe.”

 By Kat Harrold

Photo Courtesy of Optigrun

Next week the New York City Parks Department will be adding a landmark addition to their green roof research facility.  The NYC Parks Department oversees the largest know US green roof systems test facility and will be adding the Sun-Root solar living roof to their collection.

Located on Randall's Island, the Parks Department Five Borough Administrative Building houses over 29,000 square feet of test green roofs making the collection the 5th largest green roof in New York City.  The outdoor laboratory features over 25 different systems of various growing media depths.  Weather stations and temperature sensors minor the conditions on the systems and update findings every 15 minutes on their website for public comparison. 

By Kat Harrold

 Photo by ~ Goldtex

Where square footage is at a premium the demand for green space has become one of the hottest commodities.  In a high rise apartment building one might consider the options quite limited.  Try thinking outside the box, literally, and imagine all the vertical space available. Where horizontal space is limited vertical gardens offer a green oasis in a concrete jungle.  

With the right plant selection outdoor green walls make wonderful neighbors.  A green wall composed of hardy vines can provide seasonal interest with an array of colorful leaves and fragrant blossoms.  Plant selection can also play an important role in attracting birds and pollinating insects.  

In spite of their good looks, climbing green walls can be low maintenance requiring only occasional pruning and irrigation depending on location.  Steel cables and wire-mesh grids can be used to support and train climbing vegetation.

Green walls can play an important role in energy savings.  By shading the building during the summer and providing insulation in the winter, green walls reduce seasonal stresses on heating and cooling.  The ideal location for a green wall to reduce summer cooling costs is the south facing side of the building.  The southern exposure receives the most sun light which can also be very beneficial to the vines.
 

By Kat Harrold

Photos By Jorg Breuning

The Royal Caribbean Cruise line Lawn Club exemplifies the very finest in green roof design and engineering, providing the exquisite presentation and luxury Royal Caribbean guests have come to expect.  The apply named Lawn Club is featured on cruise liners Solstice, Eclipse, Equinox, and Silhouette.  In addition to lawn games such as bocce, golf, and croquet, some of lawn clubs also features a hot glass show, cook to order grill, and lounge.

Normally, a lawn of this caliber requires a soil depth of at least a foot.  Due to weight restrictions, a modified green roof system with subsurface irrigation was engineered to provide a light weight solution with a 5 inch profile.  A surface irrigation system with hand watering is also employed to flush excess salts from the lawn.  All run off from the system is collected and treated on the ship.    

A specially selected grass mix allows the lawn to remain lush and green despite stress from salt, changes in latitude, and foot traffic.  A team of highly experienced golf course specialists are on staff to ensure 24 hour monitoring and the health of the lawn.   

The Lawn Club has been such a huge success Royal Caribbean will be adding yet another Lawn Club to their latest ship scheduled for completion at the end of 2012.

By Kat Harrold

Photos by ~ Kat Harrold

Sedums may be great for the hot dry climate of the green roof there are more colorful accent plants to consider such as bulbs.

Early spring when sedum album is just starting to wake from its winter’s nap Snow drops (Galanthus nivalis) spring forth with their deep green foliage and delicate white flowers.    

Other excellent spring bulb choices are dwarf iris, crocus, daffodils, tulips, and chionodaxa.    As the seasons progress, splashes of color  can be added to the roof with bulbs such as allium and cyclamen in summer and early autumn.  

Many of these bulbs are native to the harsh environments of the middle east and western Asia making them perfect candidates for the green roof environment.

The general rule of thumb when planting bulbs on a green roof is to cover the bulb with 3 times with the amount of growing media as its height with the crown facing upwards.  In other words if you have a 1 inch tall bulb you want to cover it with 3 inches of growing media.  Therefore, larger bulbs will have greater success in deeper green roofs with a 4 inch or greater growing media depth.