Jorg Breuning, owner of Green Roof Service LLC, together with Katrin Scholz-Barth, first introduced the German FLL-Guideline for the Planning, Execution and Upkeep of Green-Roof Sites to green roof consultants and companies in the USA in April 2002, during an ASTM subcommittee meeting in Pittsburgh, PA. The two German green roof experts strongly recommended implementing this detailed Guideline to improve the American green roofing industry, green roof systems and to develop standardized and certified green roof growing media.
Most professionals at the time said that the FLL cannot apply here in the USA because in their opinion "the US is different." Today – 10 years later we know that the FLL is widely accepted, and that nationwide, extensive, semi intensive and intensive green roof systems installed according FLL perform better. Even nationally acknowledged institutions like ASTM, NRCA, SPRI, DIN-EN and the insurer FM Global utilize the FLL-Guideline for their purposes.
The FLL guideline is not a how-to handbook. The FLL guideline helps installers to understand modern green roof technology, different green roof solutions, and the function of green roof systems or the necessity of green roof components. The FLL also helps in resolving critical roofing details, choosing root resistant roofing materials, and providing parameters for a proper green roof growing media / green roof soil. Whether the intent is an extensive, semi intensive or intensive green roof, any aspect is scientifically and logically documented in the green roof guideline.
At Green Roof Technology we assist our clients by providing this important information, and we explain the details for the specific project. The FLL is one important tool for designing any living roof system, eco roof, granular drainage system, drainage board system, modular green roof system or for selecting green roof plants.
The German Landscape Research, Development and Construction Society (FLL) is an independent non-profit organization. It was founded in 1975 by eight professional organizations for “the improvement of environmental conditions through the advancement and dissemination of plant research and its planned applications.” The FLL green roof working group is only one of 40 committees which have published a long list of guidelines and labor instructions.
The FLL has been working on standards for green roof technology for more than 30 years. Their Guideline for the Planning, Execution and Upkeep of Green-Roof Sites (FLL-guidelines) reflects the latest developments in German acknowledged state-of-the-art technology. Although the guidelines don’t give solutions for all green roof problems it is a basic tool for the construction of reliable and high quality green roofs worldwide, not just in Germany.
The latest edition dating January 2010 has been released in an English version. From the legal standpoint this German guideline cannot substitute or stop future American standards, but they are a very good source of reliable information which is based on the experience of almost one billion square feet of green roofs built.