Search
Back to Home Page
Home   |   Contact Us Ph: 443-345-1578

Green Roof Technology Blog

Water-to-Air Ratio GreenRoofs101

Green Team at Green Roof Technology, - Tuesday, March 17, 2020

Why is AIR-to-WATER Ratio on Green Roofs so important?

The air-to-water ratio is the ratio between air and water in the pores of a media. (Download PDF: click here)

 

By Green Roof Expert Extraordinaire Jorg Breuning, March 2020

 

Introduction (Challenges)

On ground disconnected structures like roofs the available rooting space for plants is typically limited because of weight restraints. Additionally the Green Roof components and the plants are exposed to more extreme environmental impact like higher wind speeds, reflecting surfaces, higher temperatures, air pollution, artificial light at night, lower bio-diversity and more. Water to Air RatioIn such locations the Air-to-Water ratio within the Green Roof system can fluctuate much more often beyond the desired range what causes stress on the plants and stress on beneficial microbes. 

If more extremes are expected, selecting the right plants and right Green Roof system is crucial. In some cases an irrigation system (temporary or permanent) or enhanced drainage system should be considered to reduce stress conditions on the plants and to improve soil biology. However, operating an inappropriate irrigation system (like sprinklers) or drainage systems that were never engineered specifically for Green Roof applications can be counterproductive because the Air-to-Water ratio is not considered. Constant adverse Air-to-Water ratio is the problem on over 60% of the Green Roofs in North America and with changing weather patterns this problem is getting worse.

 

What is AIR-to-WATER RATIO (Introduction)

The vast majority of plants used on extensive or intensive Green Roofs thrive best within a specific Air-to-Water ratio range in the root zone of a Green Roof system. Over the course of a year and depending on weather conditions, a Green Roof system’s desirable the Air-to-Water ratio shall vary between 35/65 to 65/35 (65% water/35% air to vice versa). An Air-to-Water ratio in such a range is important for the resilience of plants, for nutrient exchange capacity, pH buffering capability, and beneficial (aerobe) microbes. Peaks in one or the other direction (adverse Air-to-Water ratio) can be tolerated by the plants if this is temporary and very limited in time.

To successfully reduce adverse Air-to-Water ratio it takes, extensive experience, profound horticultural knowledge, understanding the historic developments, seeing environmental/natural facts, and the ability to evaluate natural indicators on existing Green Roofs. 

 

Understanding Green Roof Systems 

As long as humans have cultivated plants they have learned that natural parameters in biology, physics and chemistry are given and everything has to collaborate within these nature’s laws. Although we are able to Gen-manipulate plants for better yield, more pest resistant, and for more stress resistance, but the nature’s laws won’t change.

An increasingly number of stormwater professionals recognize that Green Roofs are an excellent, the least expensive and most natural stormwater management tool with many added values for the environment we live in.  However, as often we talk about Green Roofs as often these specialized professionals forget about the Quarterbacks or key players of such systems: the plants!

It is a simple fact that the more we do for healthy plants with a natural diversity, the better a Green Roof system can retain and detain stormwater.   

Within the development of modern Green Roof technology over the last 50 years most Green Roof systems are built with different continues layers.

The basic layers are (from roofing up): Green Roof System -typical

 

  1. Protection layer to separate between roofing and green roofing trade and to protect the underlying components.
  2. Soil/Media extension layer (often described as drainage layer) to mimic natural soil profiles and avoid anaerobe conditions in rooting zone.
  3. Filter layer that avoids fine particle migration within the system.
  4. Engineered Growth Media or soil that meets parameters of FLL*.
  5. Vegetation.  

 

INFO! Trays, pre-planted containers or modular systems try to mimic the same layers within a small defined area like a plastic box, metal container or soil filled bags. These systems are solely made for easy shipping which is blink of eye in the life span of a Green Roof. These systems are not continuously installed and so these systems are considered as a temporary solution for a limited time (5-8 years).  In most cases these planters or trays are getting re-planted or removed over time, many already ended up on landfills.

 

Understanding Green Roof Plants

Because of the highly fluctuating Air-to-Water ratio, experienced Green Roof designers prefer utilizing hardy plants. Ideally plants that can cope with no irrigation, that are more resistant to drought and temporary extensive water, that are more heat and wind tolerant, and vegetation that can fast regenerate after stress.

In most cases and on shallow extensive Green Roofs succulent type of plants (like Sedums) are often the preferred and common choices.  Even so the Sedum family is very large, colorful and low growing, for enhanced resilience they also rely on competition with other plant species like mosses, perennials or grasses of comparable hardy properties. Horticultural experts call this “natural plant diversity”. Such natural plant diversity stands in a full contrast to Sedum monocultures that often come with tray (modular) systems or systems with pre-vegetated mats. Pre-cultivated systems are very popular in North America where instant gratification and more revenue play a pivot role.

The variety of different plant families or allowing a natural diversity increases root activity within the Green Roof system, creates healthy rooting space, soil structure and texture, with desired micro and macro pores for enhanced soil biology, all resulting into a more ideal Air-to-Water ratio, better water retention and increasing stormwater detention.

Understanding the Current Green Roof Industry

With the focus and current trend on stormwater management, it is “natural” that many people try to improve the stormwater managing ability of Green Roofs. In this regard the Green Roof industry is not getting tired in developing a deluge of products and components that are supposed to help with stormwater management, stormwater retention, stormwater detention, stormwater neutralization, and stormwater clarification. Unfortunately most of them are forgetting about the champions; the Plants!

Interestingly many of these innovators are often highly decorated with desirable titles, have done a lot of commercial reductionist research, micro- and selective-research over a short time with floods of data, have written a lot papers that are piling up in the cloud, and they have introduced new words or terms that sound fancy, makes them look trendy or educated.

 

Learn From Common Sense

Our ancestors preferred Green Roofs as an extension of living green and private recreational space, for growing supplemental food or for building protective purposes. Today’s trend moves away from insulating purposes (because that was wrong in the first place) to stormwater management. Environmental aspects go under in the craving for a Return-of-Investment (ROI). With an entire Armada of specialty Green Roof products, with an army of engineers, and a deluge of data people are trying to narrow-down a living machine (a.k.a. Green Roof) into a static, man-made tool by altering, avoiding or eliminating natural processes which are elementary for healthy and resilient survival of plants/vegetation. It is like feeding less to livestock to reduce Methane gas emissions.    

Some of the problematic and counterproductive specialty Green Roof products are:

  • Very thick layers of synthetic fabrics with increased retention and/or detention capacity based on internal capillarity properties or hydrophilic properties. These specialty fabrics often reverse natural capillarity of engineered soils what dries out the soils faster or when infiltrated with organics particles there is waterlogging and rotting.

  • Some Retention and Detention/Drainage Boards (mainly made from plastic) have no time-release overflow or no overflow that allows air between the water reservoirs. Not talking about polystyrene plastics that are bad for the environment in all regards.

  • Water Crystals, Hydrogels are small chunks (or crystals) of man-made, water-absorbing polymers. The chunks are like sponges – they hold a tremendous amount of water by increasing in size. The liquid is then supposed to release gradually into the soil.  These products have a limited lifespan that is generally less than 1/10 the lifetime of a Green Roof and so not worth the investment.

  • Mineral Wool is a manmade material from glass fibers either spun together or adhered together. Beside that mineral fibers are a possible human carcinogen these specialty products support an Air-to-Water ratio from 95/5 to 5/95 (95% water/5% air to vice versa) whereas the strong water holding capacity /waterlogging is much longer than in natural soil profiles and creates temporary anaerobe conditions = water stress on succulent type plants and root rot.
  • High organic content (over 50%) in growth media (soil). Decomposing of organic matter increases biology activity which is related to heat, causes unusual nutrient increase or decrease, and an increase of carbon dioxide in the soil profile. This and the additional risk of waterlogging increase the stress on plants.
  • Slow release or fast release, solid or liquid fertilizers of synthetic/chemical origin behave on extreme locations like roofs very different to on-grade applications. Especially in combination with the above specialty products there could be a serious and snowballing risk for the vegetation and the environment through run-off. It can increase salt concentrations or chemical process that cause deterioration of other components (e.g. roofing) of the Green Roof or the structure.
  • Chemical weeding Chemical weeding is a common practice mostly used in North America where environmental laws and standards are very low. Chemical on extremes locations behave very different to on-grade locations and succulent type of plants that have a slower metabolism what means they might die very slowly. What looks like chemical “resident” may be affect such plants years later, weakens them and exposes them to other diseases easier.


Conclusion

Vegetation placed on ground remote or ground disconnected location is a century-old tradition for very different and combined purposes. Optimizing only the aspect “stormwater” will ultimately affect all other natural cycles within a Green Roof system. Especially in North America these considerations for natural cycles on a Green Roof are often not known, disregarded or purposeful ignored for a desperate craving of profit and ROI.

This might looks like a society accepted approach but it can result that Green Roofs in North America might not get as popular and as accepted as in European countries where commons sense, decades of monitoring, fundamental education, and solid experience is the driver for their success. Most countries in Europe understand that healthy driven plants, plant diversities and plant communities on roofs increase the benefits as they progress, develop, and generate a natural ecosystem.

End

Net-Zero Townhomes Benefit From Solar Garden Roof

Green Team at Green Roof Technology, - Saturday, November 30, 2019
Net-Zero Townhomes Benefit From Vegetated PV Roofs
This suburban Washington, D.C., project proves there's no need to choose between a green roof or a photovoltaic roof



Developer-builders Jessica Pitts and John Miller of Flywheel Development had a goal and a problem with their Perry Street Townhouses project. Their goal was to build affordable net-zero townhomes in suburban Washington, D.C. Their problem was stormwater management: Rules in Prince George's County, Maryland, required them to detain the runoff from heavy rainstorms on-site, rather than divert it into municipal storm drains. The poorly draining site soils and the tight site precluded traditional ground-based stormwater best management practices, so they looked to a vegetated rain-detaining roof for a solution. But Pitts and Miller also had other plans for the roof: They needed solar power to meet their ambitious energy goals.

In the end, Pitts and Miller reached both of their objectives with an innovative combination: a vegetated roof whose growing medium captures significant amounts of rainfall, with solar arrays mixed in with the plants and supported by modular frameworks that are anchored and ballasted by the green-roof growing medium. Manufactured by German firm Optigrün, the PV array support system is imported from Germany, and the pair say this was the first time it had been deployed commercially in the United States. But Miller says the idea is a "no-brainer" financially: "Because the solar racking is ballasted by the green roof media and the plants that keep it from blowing away, that percentage of the green roof that is ballasting the panels is also eligible for the federal tax credit for PV." The roof is also effective as a stormwater management system.

"The solar green roof is designed to detain between 1.8 and 2.4 inches of rainfall," Pitts says. "There is little to no runoff from a small storm of about 1.2 inches or less, and runoff increases as the rainfall increases."

The process started during the design phase. Says Pitts, "This can go on any sort of deck. Our structures are wood framed. But you have to account for the load that you’re going to be carrying with the engineering, so it’s important if you do this, to have a mind to do it at the beginning."

"Wind uplift is a critical calculation on the solar," Pitts continues, "and the depth of the green roof media is determined by wind uplift calculations. We actually had a 3-foot parapet wall on three sides of the roof, and the PV system is down below that level and is protected from wind uplift on three sides, which reduced the depth of the green roof media that we needed to install."

The green roof media would help to protect the building's EPDM roof from sunlight and weather. But the green roof and solar would also impede any needed repairs or maintenance down the road. So Pitts and Miller decided to install a leak detection system before laying down the roofing.

"We thought it was prudent to install a leak detection layer—it's a metal mesh that goes underneath the roof membrane," says Pitts. "What that allows you to do is that if you ever get a leak, you can identify the exact location of it."

The thin stainless steel mesh comes in rolls and is installed directly to the roof deck before protection board and roofing are installed. "It looks like chicken wire," says Pitts. "There are two leads that you can run up the side of your parapet wall and hang out at the top. And you can test even before you put the green roof on. We had the people come out and test the membrane as soon as it was in place. They wet down the roof and apply an electrical charge and they look for places where you get a connection."

Miller explains that the leak testing crew uses a detector that looks like a push broom with metal bristles. "They found five or six little pinprick holes that you never would have noticed, and we patched them," he says. "All you have to have is a roofer maybe bends over and maybe one of the metal brads on their jeans pokes a hole in the roof, or they drop their utility knife, and you would never know. The leak detection crew will circle this spot with a Sharpie, and you’re like, 'Wait a minute, that’s a hole?' But this way you know on day one that your roof is leak-free. And if you have a future problem, then you can find it."

Next comes the layers of the green roof, which are integrated into the high-density plastic bases for the solar array racks. "You have your plastic protection layer, which keeps the roots from growing down into the actual roof itself," Pitts says. "Then you have a protection mat, which is kind of like a felt material. That’s for protecting the roof membrane from the roughness of the growing medium. Then you have a geotextile mesh, and the mesh that we were using has large holes in it—it’s a loose weave—and that goes on top of the bases that the green roof ballasts down."

The mesh wraps under and around metal edging at the roof perimeter, and it runs over the PV rack bases. An L-shaped metal bar is installed into each of those bases, and then the rack is accepted into those metal L bars, according to Pitts. Each grouping of panels is also tied together. "We had four individual systems on top of each of the four individual homes," Pitts says. "So each panel grouping becomes linked together, and then they all become linked together through the geotextile mesh."

Next it was time to place the growing medium. "It’s very common to have drainage trays and things of that nature to help reduce the depth of green roofs, but we wanted it to be thicker because we are using the weight of it to hold down the solar," Pitts explains. "We had a green roof media company (Mulch Solutions of Falls Church, Va.) come and blow the media up onto the roof with its blower truck."



There were two types of media: a larger, heavier drainage medium as a base layer, then a layer of growing medium on top of that, separated by a layer of fabric. The entire placement with the blower truck took less than a day. Besides the efficiency, says Pitts, another advantage to the blower truck is that it avoids creating point loads on the roof during the application of the growing medium.

"And then the plants arrived," says Pitts. "There are two different types of green roof plants. There are ones that grow in sun, and there are ones that grow in shade. So we had to demarcate the locations behind and beneath the panels, and allocate the shade plants to those locations; and the sun plants went everywhere else. And then we got all the PV equipment, and the PV panels came up last."

The Perry Street Townhouses were completed in spring 2017, and the plants on the roof are spreading nicely over the growing surface. "Green roofs really require a lot of care and feeding in their first couple of years to get them to establishment," Miller says.

Flywheel Development is currently working on two more affordable net-zero developments in Washington, D.C., Stack Eight and Cycle House, slated for delivery in 2020 and 2021, respectively.





Mineral Wool in Green Roofs – From Zero to Hero?

Green Team at Green Roof Technology, - Saturday, April 13, 2019

 Mineral Wool in Green Roofs – From Zero to Hero?

The use of Mineral Wool in Green Roof applications is an increasing trend in North America and in countries where such industry is still young or focused on fast profits rather than on longevity.

 

One selling benefit of Green Roofs is the extended lifetime of the underlying water proofing because the Green Roof protects the roofing against the elements. Can Mineral Wool stand up to this?

Against any semi scientific promotional material from Mineral Wool applicators, the market share of mineral wool in the German Green Roof construction industry is around 0.1% or out of 100 million square foot new green roof construction every year (Germany) it is only around 100,000 sf/year.

The reasons for this marginal market share are simple:

  • Mineral Wool has shown a drastic loss in performance after 5-7 years.
  • Mineral Wool is engineered for nurseries and for only one growing cycle.
  • Mineral Wool fibers are considered “hazard” in Europe.
  • On extensive Green Roofs the water retention and water-air ratio is unsuitable for succulents.
  • Mineral Wool expands and contracts in wet-dry cycles.
  • Mineral Wool is hydrophobic and can dry out the traditional overlaying growth media faster.
  • Mineral Wool growth media boards require ballast.
  • Green Roofs with Mineral Wool are difficult to repair, replant or recover.
  • Mineral Wool interrupts natural soil profiles (unnatural soil profile).
  • Mineral Wool is an additional installation step and related to higher costs.
  • Some Mineral Wool products compress under the load of ballast (soil).
  • Some Mineral Wool products contain Phenol resin or Phenol-Urea-Formaldehyde resin as binder and these products can hardly be recycled. Ecose technology is environmentally better but it doesn’t eliminate other problems mentioned here.
  • Reuse of all types of Mineral Wool for the same purpose is only possible after a (non-existing) difficult remanufacturing process.

 

An inexperienced green roof installer might like the idea of an obvious simple installation. However, what looks nice in a brochure doesn’t necessarily reflect the reality. Ballast on the Mineral Wool boards is still required and this requires different equipment. The setup costs for additional equipment are the same whether small or larger amounts of ballast ( or ballast reduces the setup costs).

Engineers might like the tremendous amount of water retention of Mineral Wool. However, they forget that plants (vegetation) have a very specific need for a balanced air-water ratio. If engineers plan the use of succulents (like Sedums) such air-water ratio is even more important (emphasis on air). Engineers are not horticulturalists.

Mineral Wool is widely used in nurseries for one-season vegetables. After this growing season the Mineral Wool (often combined with plastic) ends up on landfills. In 2008 it was around 200,000 tons of hazard waste in Netherland alone. Further, nurseries are growing their crops under highly computer controlled conditions for nutrients and air-water ratio in green houses. Who wants to sell a nursery to a building owner with roof under the sky?

In general shouldn’t we like Mineral Wool in Green Roofs? Mineral Wool gives us lucrative additional jobs in the future for repair or replacement (job security…).

 

 Photo: Repair, Reuse - impossible

I am a lifelong green roof professional and I stand up to my principals with the promise that a green roof should last as long as the building – and that the materials can be reused for the same purpose after that and without processing (there are many fancy names in advertising for it, like cradle-to-cradle etc.).

Like me many people don’t care about fancy word creation and they stand for and what the American Green Roof industry should stand for uncompromised quality and doing things right. Quick profits, instant gratification or senseless warranties don’t promote the trade of professional Green Roofers and it is certainly not my philosophy.

Mineral Wool is: From hero to zero.

 

I appreciate reading my opinion, based on 4 decades of Green Roof experience from all Green Roof friendly places in the world.

101 Common Sense of Intensive Green Walls

Green Team at Green Roof Technology, - Monday, September 24, 2018

People like to make statements – environmentally friendly statements. For such statements, Intensive Green Walls are often utilized.  Intensive Green Walls are systems where the roots of plants are in vegetation carrier that is mounted to a vertical surface. Because of gravity it takes some technical efforts to supply the plants with their essential needs like nutrients, water, air, and light.

 

Picture: Schöner Wohnen

All these systems have bits, parts and materials that are man made and that wouldn’t be required on a natural horizontal area (e.g. Green Roofs). These materials are often made with a high input of natural resources.

The amount of man-made materials and the time needed for the installation makes intensive Green Walls rather expensive. They might start at around $90.00 per square foot but can go up to $150.00 or even more per square foot. An extensive Green Wall (with climbers) is somewhere between $1.00 - $20.00 per square foot. Extensive Green Walls only need a portion of natural resources and patience (what most people don’t have).

More impressive  are the operational costs of intensive Green Walls (“average fuel consumption”):

Water: Daily consumption between 1- 1.5 gal of water per 10sf and per day.  Pump:  1 kWh/day/10sf

Nutrients: Specially manufactured liquid nutrients per fertigation system $0.05-$0.10 per 10sf/day plus 200Wh/day

Light (if indoors without outside light): Approximately 2 kWh per day and 10 square foot  – assuming light duration 14 hours a day.

Plants: Indoor greenery typically doesn’t have native plants (where are all these native plants advocates?) and require subtropical conditions that require certain room temperatures (energy) and can cause corrosion with HVAC systems and ducts, besides spores and mildew.  

Maintenance: 1 man hour per two weeks per 10 square feet.

I understand that every intensive Green Wall supplier has great arguments and technology to lower operational costs (likely increases the setup costs and failure). Whether by using rain water, grey water or Solar/Wind energy, or even an industrial byproduct for fertilizers, everything is related to the use of natural resources that could be – potentially – used for other and more important purposes than just making a statement or showing (fake?) environmental cautiousness. Intensive Green Walls are a piece of art. Being an artist and working with living plants is not automatically being environmentally friendly nor it means being an environmentalist.

Even so intensive Green Walls likely create environmental awareness to a broad audience; it is still on the back of using natural resources - ineffectively. So you have to decide for you own and keep in mind that replacing an intensive Green Wall (because of operational costs) likely helps to fill landfills.

Picture: BuGG

For me (in my opinion). Intensive Green Walls are a wrong signal because it could be done much more efficient and with the patience of a true gardener who is in harmony with nature.

Jörg Breuning

An Exceptional Green Roof

Green Team at Green Roof Technology, - Monday, February 27, 2017

Sufism Reoriented Sanctuary

 

An Exceptional Green Roof

After more than half a century in temporary quarters, Sufism Reoriented now has a permanent home in Walnut Creek, California. Designed under the guidance of Murshida Carol Weyland Conner by the distinguished architectural firm of Philip Johnson Alan Ritchie, the new sanctuary is set among serene gardens on three acres of land in a suburban neighborhood about twenty-five miles east of San Francisco.

Alan Ritchie’s design perfectly realized Murshida Carol Weyland Conner's vision. Brought to fruition by the Architect of Record, Soga + Associates Architect Inc, this beautiful design is to endure for over 700 years. The building is innovative in many ways, from its curved marble cladding from Carrera, Italy, to its climate control with state-of-art air filtering systems, to its Green Roof composition with 100% recycled Foam Glass Gravel  engineered by Jorg Breuning , Owner of Green Roof Service LLC , to its storm water management with rain harvesting features to retain the entire annual rainfall, to its 33 feet tall hollow bronze sculpture with seismic base isolators and acrylic butterflies, standing inside of a 3-story tall room with curved glass guardrails.


With highly experienced architectural services and project management by Clement T. Soga, Soga + Associates Architects Inc, the Sanctuary’s construction began on May 24, 2012 and its Ribbon Cutting ceremony was held on February 24, 2017.

 

Green Roof Service LLC – Green Roof Technology worked hand in hand with Sufism Reoriented, Soga + Associates Architects Inc, and SWA Group Landscape Architecture to create a Green Roof solution that perfectly mimics the natural soil horizons with materials that will last thousands of years without compromising or limiting healthy growth of any vegetation at any time. Jensen Landscape carefully implemented the details and specifications of this new type of Green Roof under the direction of Jorg Breuning.  It is the first Green Roof in North America that utilizes Foam Glass Gravel made of 100% recycled glass on a large scale.  The ultra-lightweight material performs as a drainage and retention layer combined with outstanding structural capacities. Foam Glass Gravel is produced in the USA and in Germany according to the strict specifications of Green Roof Service LLC - Green Roof Technology.      

27th February 2017

Jorg Breuning

World’s First Modular Green Roof System

Green Team at Green Roof Technology, - Sunday, February 12, 2017

World’s First Modular Green Roof System

Modular Green Roof System

Green Roof Professionals around the globe often wonder or speculate how and when the commercial modern Green Roof industry really took off. There are many opinions and alternative facts out there but only a few really know that the hot spots with patents were in Basel Switzerland and in Stuttgart Germany for seamless or wall-to-wall Green Roof systems.

The World’s first modular (or tray) system has been developed in Stuttgart by Brecht and Hämmerle, mainly known as the Brecht System (if one doesn’t consider terracotta pots on roofs as a modular system).

The Brecht System was a basic polystyrene box with a three-layer Green Roof system. The system was available in extensive, semi- intensive and intensive planting depth. With this simple three-layer system the inventor combined many benefits in one box. All systems had a water reservoir for maximum water retention – more than any other Tray system currently on the market and more than any fabrics, foams or mineral wools, and the boxes contained standard nursery soil for a healthy fast growth and to lower costs.

There were different options for covering the less attractive boxes, with either wood or metal (aluminum). Today we call these frames around the boxes: Edging.  

Based on the polystyrene, the boxes were very lightweight and easy to install. Actually, they fitted into each other to create different heights and different planting depths. I would describe them as a Modular –LEGO-like planting system.

Unfortunately, any polystyrene as a limited lifespan when exposed to UV or biological activity and so many of these roof gardens had problems after 5-10 years. Further, many of the plants rooted out of the boxes (drainage holes) and penetrated the waterproofing.

Around 1992 the last Brecht System was removed and replaced by wall-to-wall or seamless Green Roof systems. All of these Green Roofs are still existing - if the building still exists.

The Brecht Modular Green Roofs system had also other issues that are similar to the currently existing systems. However, nowadays the tray systems use metal, other plastics, and mainly with irrigation systems. This makes them last longer, but as often only delays the point of failure. The roots of plants and the biological activity on healthy Green Roofs are often underestimated as well as the functional lifespan of foams, polystyrene drainage mats, and mineral wool products.

Norwegian Green Roof Log Cabins in the USA

Green Team at Green Roof Technology, - Wednesday, February 01, 2017

Norwegian Green Roof Log Cabins in the USA

Sloped Green Roof

Around 50 years ago there was trend in the USA of having Norwegian Log Cabins as a second home.

All of these cabins came entirely from Norway and they all had a Green Roof. Most of these cabins with timber from Norway still exist and the owners are very proud of having these solid, cozy and unique structures.
Unfortunately most of Green Roofs have been replaced by metal roofing during the last 20 years.

Nevertheless the simple Green Roof systems (without plastics) lasted at least 3 decades without major maintenance and without any irrigation systems. Even Fire Marshals never had an issue with this unique long lasting roofing solution.
Around 12 years ago I had the honor to meet a building owner, who wanted a Green Roof back and as it was originally designed. The project was near Washington, DC and meanwhile the building was surrounded by 60 feet tall trees and entirely in the shade. The structure was still able to carry around 30psf for the Green Roof.

Finally, with a new roofing and a divided drainage system in a multilayered, seamless Green Roof the owner was satisfied with the result. Look at the picture (from 2015) and tell me what you think.

There is no irrigation system, no single source warranty, very limited use of plastics and very limited maintenance.



See more: Click Here
 

How to Maintain a Green Roof During Holiday Season

Green Team at Green Roof Technology, - Monday, December 19, 2016

Green Roof Maintenance During Holiday Season

Do it like Santa Clause!

During Holiday season, Santa Clause and his Reindeers simply enjoy their Green Roof. Certainly, every Green Roof requires project specific maintenance and when this is well organized, professional, and done by experienced people, there is no reason to be concerned. Something the Easter Bunny even knows while he eats the fresh lettuce on a roof top farm.

In the southern hemisphere, the year-end is during summer and all above applies as well.

The reason why this works around the globe: Plants cannot read a calendar. They are much more advanced and able to adjust to the current conditions in no time. They take every day as it comes and with a row of days they “know” in what direction they have to adjust and prepare.

If there is a problem on a Green Roof, it is typically caused by humans and their desperate conception of tidiness or hopeless desire to control nature. Whether they try doing by squeezing many plants in a tiny plastic box, using endless “engineered” layers, use materials that might serve a different purpose, or run an irrigation system whenever they see a weather application alarming them on their smart phones.

Sometime people like train plants to do what people want and create a dependency of the plants on humans. If you are such a control freak you might have a lot to do during the Holiday Season.

Green Roof Service LLC – Green Roof Technology does what the plants need and want. We understand the plants. Hence, our clients and we can lean back during the Holiday Season and enjoy this fabulous time with friends, family, and our pets – in house, outside, or on the Green Roof.

Happy Holidays!

Solar Garden Roof team and

Jorg Breuning and GRT-Team

see also:  Winter Maintenance for Green Roofs

Natural Blow Job

Green Team at Green Roof Technology, - Monday, May 30, 2016

Natural Blow Job

Like an endless army of parachutists released from an airplane, seeds and fruits travel the wind currents and gentle breezes of the earth, possibly colonizing a distant mountain slope or fertile valley potentially 1000 miles from their origin. Literally hundreds of species in many plant families have adopted this remarkable method of dispersal and make the promoters of native plants look like a fool.

Imagine a little parachutist seed can fly 1000 miles in ten days it still takes probably 20-30 generations and 15-20 years getting around the globe. Seeds found in hail or high altitude air samples confirm that this is not a fiction.

Plants have very limited mobility and consequently rely upon a variety of dispersal vectors. Wind is only one and there are many other smart ways. The easiest might be humans. If a plant gives humans a trade-off (nice flower, fruit etc.) they can carry them as far and nowadays in a much short time.

Relocating to a faraway location isn’t always successful but it is necessary for the specie to survive in evolution where natural and manmade forces might eliminate the original place. Especially under fast changing climate conditions it is important for specie to stay flexible or to mix with similar species to create more resident ones.   

Comparing to this smart and self-sustaining way of plants, many humans make themselves to fool by either helping to transport the plants or by categorizing plants into native and non-native.  Doesn’t it sound like schizophrenia when you get a LEED point for native plants on a 500sf Green Roof downtown Manhattan and at the same time(GMO) corn is grown on almost 100,000,000 acres across the US?

There is no question that the worlds Gen-pool of all organisms must be preserved but the way as it is approached seems in most cases unprofessional and desperate.  Being 45 years a gardener, I understand that nature has its own way – we can be part of it but we can’t be the director of it.

 

Green Roof Failures

Green Team at Green Roof Technology, - Wednesday, May 18, 2016

Do Green Roof Failures increase with Roofing Manufacturers?


 

 

In the last two days I visited four of my projects that are between 14 years and 1 year old.

Each of these Green Roof has an own interstesting history and with the exception of the “cozy” Green Roof, each of the extensive green roof host over 25 and 40 plant species in excellent health.

None of them was ever irrigated and the oldest was fertilized the last time 10 years ago. All of them require hardly any maintenance (2 hours per 5,000sf / year).  One Green Roof is maintained only once every 3 years.

 

For these amazing, inexpensive and resilient green roofs a special thank to all who participated!

 

In contrast:

I was on one roof that was installed and maintained by a roofing company with materials from a famous roofing manufacturer.   This roof is basically going down the drain because of incompetence, sloppy work, and inappropriate materials.

This roof came with a costly single source warranty that –as always – doesn’t cover anything of the green roof. The cost for this worthless application was around 25% higher than a fully functioning Green Roof from well trained gardeners.

 

This is one of many projects around the Nation where I am questioning myself whether roofing manufactures and roofing companies should work in the Green Roof field. As a matter of fact in last decade 90% of roofing manufacturers offered Green Roof Systems that consistently underperform or that are not maintained properly. Actually most of these manufactures changed their systems and approaches to Green Roofs more often than they changed the management of these multi-million Dollar corporations. 

While many of these manager focuses on how increase revenue and some of them how to fix the problems with Green Roofs their quality of the waterproofing and craftsmanship of their installations went down. Striving for more revenue is not a wrong thing in general but when this is done on the backbone of the Green Roof industry and our all prospect clients it is more than questionable.

As client you have to figure out whether it is more important to make unknown stockholder happy or yourself.

I don’t fall for roofing warranties and sales forces with nice brochure

This particular roof will be recovered by an extensive weekly maintenance program until the end of the year and a monthly maintenance program for the entire next year!  

Follow Us!

RSSGreen Roof Tech Blog
RSSGreen Roof Plant Blog


Recent Posts


Tags


Archive

Latest Blog Posts
  1. Water-to-Air Ratio GreenRoofs101 Green Team at Green Roof Technology, 17-Mar-2020
  2. Net-Zero Townhomes Benefit From Solar Garden Roof Green Team at Green Roof Technology, 30-Nov-2019
Facebook   Twitter   LinkedIn   Google+   YouTube
Go To Resources Page