GREEN ROOF SYSTEMS
ALL UNDER ONE ROOF
What is your Green Roof system?
This question arises nearly every day, much like asking an architect, "What does your house look like?" Just as architects can create anything from small garden sheds to towering skyscrapers, we design greenery and Green Infrastructure that seamlessly aligns with the design intent, ecological needs, and economic limitations.
Green Roof systems are composed of several layers that collaborate to create a comprehensive system. Some companies offer pre-assembled systems, typically in the form of plastic trays, while others provide a variety of layers that can be tailored for different types of Green Roofs. Furthermore, some companies emphasize unique components—often made of plastic—to differentiate themselves in the market, sometimes coupled with questionable warranties to entice customers. However, the crucial question remains: do all these features genuinely promote resilient plant growth?
Our Green Roof System
Just as architects operate within a variety of parameters, we also do the same, selecting the best options to fulfill all the unique requirements of each project.
The outcome will be a Green Roof System that prioritizes the plants above all - because that is the primary reason for implementing a Green Roof. The utmost support for the vegetation aligns perfectly with the building owner's diverse intentions, which can vary significantly across economic, environmental, aesthetic, functional, or technical dimensions. At this stage, one-size-fits-all (like tray systems) Green Roof solutions have reached their limits or necessitate compromises that ultimately disadvantage the vegetation, leading to expensive failures.
One alternative is to let Roof Manufacturers decide on the Green Roof system by relying on their attractive brochures, their argument for a single source, and their warranty promises. Based on experience, this option usually ends up costing about 40-60% more than solutions that are specifically designed by Green Roof Technology. Additionally, these warranty promises are closely tied to very high maintenance costs added to keep warranties alive. Despite the high costs, there's still a significant risk of failure, and many parts are excluded in the fine print.
Our green roof system pays off during the process already and is designed to last as long as the building it’s on. Proactive roof condition evaluation systems can benefit the owner more than warranties do, at a much lower cost, and they provide status reports automatically or whenever needed.
In any case, if you choose to go with a prefab or Green Roof tray system or even a green roof system from a roofing manufacturer, we are here to offer our experienced perspective for a thorough review, also known as Failure Mode and Effect Analysis (FMEA).
Green Roof Technology's renowned independence from manufacturers and suppliers enables us to deliver exceptional value to our clients.
Schematic Overview of Available Green Roof Systems
Trays/Modules
Plastic Boxes, Container
Concept
Only Extensive
Layered SE
Sponging Elements
Concept
Mainly Extensive
Layered GD
Granular Drainage
Blue Roof Ready
Layered DB
Drainage Boards
Blue Roof Options
Monolithic
Platform Based System
Blue Roof Ready
Solar Ready
Green Roof Systems
In general, there are five (5) typical Green Roof systems on the world market:
- Tray systems.
- Layered Sponging Element systems (SE).
- Granular Drainage, layered (GD).
- Drainage Board, layered (DB).
- Monolithic Platform systems.
Green Roof System Preferences
Obviously, in younger extensive Green Roof markets (like USA, Canada, U.K., Australia, etc.) we sense a preference for tray/ plastic box systems, or layered systems with sponging elements (e.g. Mineral Wool, poly-fabrics). Layered Drainage Board systems are on the rise since year 2000 for extensive and intesive green roofs because architects like the "engineered" look of the boards and manufacturers make great profits with fossil-resource products.
With increasing experience in the mentioned markets, more environmental concerns, and economic considerations, Layered Granular Media Drainage will have a revival in the near future. This is because it is the best for the plants. Additionally the materials have consistent properties for as long as building lasts (up to 500+ years), material can be source from Urban Mining, and they produce zero waste in the installation process. Layered Granular Media Drainage systems are know - believ it or not - for more than 2,000 years in agriculture and gardening (this might not be a great point in our current plastic age).
Monolithic Platform-Based Green Roof systems intent to cover the gap between Layered Drainage Board and Layered Granular Media Drainage because for certain application there might be a lightweight reinforcement necessary e.g. Blue Green Roofs, Solar Green Roofs, Wetland Roofs, Multipurpose Roofs etc.
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| Requires Instant Vegetation | |||||
| Plugs, Cuttings, Seeds | |||||
| Variable System Thickness | |||||
| Biodiversity | |||||
| Water Retention and Detention at 6" | |||||
| Air-to-Water Ratio is key for resilience | |||||
| Saturated Weight at 6" depth | |||||
| Saturated Weight at 12" depth | |||||
| Delivery Time | |||||
| Maintenance at 6" depth | |||||
| Blue Green Roof Option | |||||
| Solar Green Roof installation at later point | |||||
| Cost Benefit Ratio | |||||
| Ecological Value | |||||
| Overall Value 1= Bad 5= Best | |||||
Tray Systems
Manufactured and grown off-site often in greenhouses and mostly with cheap labor. Tray are always in a plastic or metal containers (sizes vary) for shipping that remain on the roof.
These One-Size-Fits-All containers/boxes are only required for easy growing the plants in a nursery. Additionally, the uniform box help with shipping (grown in the shipping box). However, once the container is on the roof, it has no real purpose anymore. It is considered unnecessary.
The installation of these heavy pre-planted boxes relies on a fixed grid or checker board. Because all planters limit the root spaces of plants and critical in-box drainage, the systems have a tendency to fail. This reduces life expectancy accordingly and replacements creates more trash than necessary. Also, the high amount of unnecessary parts (that are only needed for shipping), such systems are questionable in regards sustainability and LEED ratings.
Patents of tray systems go back into 1970's and they are common/public knowledge - most existing patents on trays are worthless.
Layered Green Roof systems with sponging elements
installed directly on the roof and typically from wall-to-wall and in separate, single layers. Surely, this reduces double handling comparing to tray systems.
Sponging elements are typically Mineral Wool or thick layers of synthetic fabrics. Because sponging elements retain up to 95% of water, it makes them attractive for stormwater calculation and related marketing. Clearly forgotten with the use of sponging elements is the health of plants. Especially on extensive Green Roofs with succulents, drought resistant plants this is problematic. The wide range of Air-to-Water Ratio (95:5 - 5:95) creates extended and unnecessary stress on vegetation. Consequently, the plant diversity will change and unwanted plants dominate. In European long-term studies, systems with sponging elements failed in around 10-12 years and were replaced.
In short: The desperately search for optimizing stormwater DATA, eliminates the intention of having resilient nature on a roof. Smart roof drain controls are much more efficient and less costly.
Layered Green Roof systems with Granular Drainage Media:
also installed directly on the roof and ideally from wall-to-wall for the best protection of the roofing. Surely, this reduces double handling comparing to tray systems. After all, layered systems with Granular Drainage Media go back into the ancient world but also on patents from around 100 years ago.
The Rockefeller Center, NYC is the most famous layered Green Roof system with granular drainage media in North America. Although, constructed in around 1930, it still performs as intended without replacement. Also, without the use of plastics or metals, it is equivalent with some of our latest Green Roof solutions.
In 1977 Hans Gilgen (Optima) patented and improved this layered systems. Of course with a smart Blue Roof/Irrigation system, where the plants operate the irrigation on demand. Naturally, without electricity or Apps. We consider that as an Artesian System. Additionally, Hans Gilgen is mentor of Jörg Breuning Green Roof Technology. We are proud for having of the original documents (French/German). Layered artesian Green Roof systems with granular drainage work in all climate zones. Also, they are adaptive to climate change because they mimic the natural soil profile. The high performance granular components ensure the best growing conditions for the plants all time.
Layered Green Roof systems with Drainage Boards/Mats
installed directly on the roof and preferably from wall-to-wall for the best protection and function. In a world where plastic is cheap and with high profit margins, drainage boards and mats are flooding the green roof industry. Therefore, in our archives there are around 70 different types piling up. Unfortunately, only two handful of these meet the needs of plants or our criteria.
Especially in younger Green Roof markets most of these components have repurposed from other uses. In particular from vertical building drainage and so no good function for horizontal drainage under Green Roofs. Overall, not specifically engineered components are problematic for healthy growth of the plants. Likewise, sandwich components (where fabrics are combined with board) that are also problematic for recycling, reuse or repair. All Drainage Boards / Mats have to be cut to size on the roof. This creates additional waste and costs for Green Roof installations.
Although, Drainage Boards / Mats have great measurable, reliable drainage, retention and detention function, they also limit the rooting space for the plants. In short, Green Roof Technology has sufficient experience to decide when, where and what type of drainage/retention board is needed.
Monolithic Platform-Based Green Roof systems
The latest 21st century generation of layered Green Roof systems. Such systems are installed directly on the roof and always from wall-to-wall for the best protection and function. The flexibility of Monolithic Platform-Based Green Roof systems is far beyond any other systems. Nevertheless, it combines century old traditions with modern requirements.
Platform-based Green Roof systems create a second roof deck above the roofing that can increasing structural capacity. Certainly, it maximizes the available rooting space for the plants. Although platform based systems use a limited amount of plastics, such comes from Urban Mining. The skeleton of the platform acts as a protective structure during construction. Can be used for staging area for other trades and before the Green Roof goes in place.
From there it is a solid foundation for all Green Roof Types - even combined types in one area. The skeleton-like structure allows to secure solar panels, technical roof units, railings, micro wind turbines, and amenity items seamless and easy without penetrating the roofing. Monolithic Platform-Based monolithic Green Roof systems adjust to changing roof pitches and work from flat to sloped roofs (from 0-90 degrees!).
Monolithic Platform-Based Green Roof systems are Blue-Green Roof ready, work perfectly in any climate zone and adopt to climate change thus they last as long as the structure. See Klima Roof.
Over the last 4 decades and with the German evolution of modern Green Roof technology, Green Roof systems have developed further. Certainly, some systems are better for smaller application and other green roof systems are more efficient for large projects. Sometimes, a combination of different products can be the ideal solution.
Green Roof Technology is crafting Green Roofs from scratch for over 40 years because every roof is different. Also local climate conditions vary and the availability of materials. Especially, in regards of performance, installing costs, maintenance and efficiency a tailored solution is unmatched.
Ideally all green roof systems and green roof design comply with the FLL-Guideline and have to last as long as the building. Traditionally, German manufactures meet these benchmarks and with time we will see more resilient and sustainable systems worldwide, too.
Of course, we avoid using repurposed components on Green Roofs. These are components that were originally develop for other purposes (e.g. vertical drainage, erosion control, shipping container etc.). Such components often cause challenges for maintenance or other substantial problems in the years to come. Likewise, sponging elements. These are also considered as repurposed components (building insulation). Additionally these components affect the soil biology negatively and create an unnatural, over saturated soil horizon.
Tray or modular green roof systems are popular since the beginning of the American Green Roof industry at a time when Americans were trying to reinvent the wheel. Luckily many of these tray systems have been replaced by now and only for residential use. Thus, most of these plastic containers are used on small roofs or small retrofit roofs. Potentially a good thing and we will see.
