Norwegian Green Roof Log Cabins in the USA
Around 50 years ago there was trend in the USA of having Norwegian Log Cabins as a second home.
Norwegian Green Roof Log Cabins in the USA
Around 50 years ago there was trend in the USA of having Norwegian Log Cabins as a second home.
Construction Going Up – Ecology Going Down?
From 2010 to 2015 warehouse new construction in the US tippled from around $5 Billion to $15 Billion with all the economic benefits. 15 Billion in new construction equals around 1000 new warehouses every year or approximately 250 million square feet rooftops plus the same amount of infrastructure provision. Annually, 500 Million square feet or 8800 football fields of lost nature by building new warehouses in the United States alone.
With some of the existing warehouses, this translates to a potential of at least 1 Billion of square feet of new extensive Green Roofs every year that could retain the volume of Lake Constance that is surrounded by three countries (Germany, Switzerland and Austria) or over the double volume of Lake Powell (UT/AZ)!
Assuming that these Green Roofs are done right, maintained by professionals and without artificial irrigation, the natural and controlled succession of these Green Roofs would allow a unique habitat for many endangered species over the upcoming years.
These green roofs can also reduce the re-roofing costs by multiple billion Dollars with a related relieve for landfills and a huge reduction in energy use.
Most important however is the climate effect.
Warehouse belts surround any large city in North America. These warehouse belts with endless impervious areas actually preheat the air that is conveyed into our cities by the wind. In the worst-case scenario, these large warehouses have reflective roofing membranes that might cool the building but also increase – due to reflection – the heat in the atmosphere substantially.
Warehouse belts around cities are like a forced air heating system in a building only on a much larger scale – Warehouse belts are a wasteful forced air heating system for entire cities
Fundamental sustainable thinking and large scale long-term research hardly exists in the US, so it is no wonder that experts are likely to miss the entire picture.
Currently in the US there are no significant requirements or ecological considerations in master plans that address this counterproductive climate habits towards our cities. Actually, it seems that warehouse belts grow faster than Green Roofs!
North American ecological organizations, LEED, or other industry associations are also missing the bigger picture. They often work locally – from one block to the next, they are focused on one or two rare plants, on a distinctive bee species, butterflies or other human pleasing critters as long as there is an instant payback in popularity. It seems worth more having a highly unsustainable fully irrigated Green Wall in the cafeteria, a nice green plaque on the wall, or growing some carrots on the roof to demonstrate social and sustainable responsibility. Most marketing efforts for green washing are beyond the costs of a simple highly efficient extensive Green Roof that helps the future generations.
The United States is a great country and North America is a large continent where thinking big was always wanted and welcome. Now it seems people are getting lost in their little plastic boxes, made in China with some nice flowers and a watering can next to it.
It is very romantic but also very embarrassing.
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!
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
In our dense Cities, more and more intensive Green Roofs are being built.
Besides all the environmental reasons, building owners recognized that a Roof Garden – usable green on the roof - creates additional value with a fast and consistent payback. A building with a roof garden is simply more attractive for tenants and potential buyers.
Typically, structural loads reduce this fantastic idea to a low profile extensive Green Roof or to an intensive green roof that is landscaped with Geofoam.
All professionals know that expanded polystyrene (Geofoam) is questionable from an environmental perspective. Some horticulturalists know that Geofoam has no benefits for the plants – actually, it reduces their rooting space for the plants (grass can root up to 3 feet deep) and consequently it increases maintenance and irrigation needs. As a result, most of these Roof Gardens with Geofoam are elevated intensive care nurseries.
Hardly any Roof Garden in Europe utilizes Geofoam because of the high risk of rodents and environmental conflicts. These roofs are being built with Foam Glass Gravel. Over the last 25 years Foam Glass Gravel replaced Geofoam and eliminated all the related disadvantages of Geofoam.
Foam Glass Gravel is 95% recycled glass, has a much higher compressive strength, the roots can practically expand like in a natural soil horizon and if combined with low-tide/high-tide irrigation the water and fertilizer consumption can be reduce by up to 75%.
The savings in no waste installations, less complicated irrigation systems, in water reduction and less maintenance make this material cheaper than any Geofoam application.
European architects also like the idea that you can create any type of landscaping on a roof without any problems, fully organic and without additional components. Foam Glass Gravel allows adding walkways, roads or other structures on top of it. Foam Glass Gravel has the best lightweight – compressive strength of all mineral materials available on earth.
The picture below shows typical setups of intensive Green Roofs with Foam Glass Gravel, like nature does it and to compare how people still do it with Geofoam.
Green Roof Service LLC - Green Roof Technology is proud to be the first that utilizes this advanced Green Roof solution with Foam Glass Gravel on projects in North America for amazing and low impact intensive Green Roofs.
The main purpose of an extensive Green Roof is stormwater retention and delaying stormwater runoff amongst many other added values.
Above: An Irrigated thin layered Green Roof System – without irrigation it would be dead.
In the last decade in North America, we've seen many Green Roofs where the intended plants never really flourished. I estimate that in the US at least 50% of the green roofs are not performing to their fullest potential. This can be observed by simply looking at the most obvious of indicators, the plants themselves, regardless if they were planted on purpose or somehow found the space to take root.
Most of these less healthy extensive Green Roofs are thin-layered systems, pre-planted boxes (often called modular systems or hybrid systems), Green Roof Systems from roofing manufacturers with ineffective components, single source warranty-systems, or design intents without consideration for the needs of plants. Typically these systems much more costly (whether thin or thicker) and the mid to long term results are often far below systems that are assembled in place with common sense.
Thin-Layered system with irrigation - doesn't work and doesn't retain much water
We all know that the transition from being a common nursery-grown plant (including pre-planted boxes) to the extreme environment of a rooftop poses severe challenges. Green roof plant nurseries typically have "great" advice and recommend the installation of temporary or permanent irrigation systems. In some areas this might be helpful when operated correctly but in all cases this advice is defeating the purpose of an extensive Green Roof (water retention). In almost all cases any type of irrigation caused a spiral of failures and it is wrong to irrigate extensive Green Roofs in areas with limited water for the cause of just having a green roof (Green Washing). Most company sponsored experts don’t see the entire picture or they only see the short term profit and commission (“Mow-Blow-Go”).
If a problem occurs and since many Green Roof system developer lack the proper and specific green roof horticultural knowledge, they may not be able to identify problems by simply looking at the indicators (the plants). This could cause the problem to gain momentum. In addition, the false conclusion that technology (Google search, Apps, synthetic growth media or sophisticated soil moisture control devices) can fix the problem supports my theory of hardly experienced or misinformed green roof professionals. They rely heavily on technology to fix any issues and miss the big picture.
Nature has the ability to take care of itself, as long as the appropriate design, materials and plants are used in addition to being familiar with the immediate location and climate.
Thin layered, super lightweight systems or systems with “innovative” components are just by physics not meant to retain “more” stormwater for the plants or they retain too much water for specific plants. As a matter of fact the costs for retaining stormwater in thin layered systems are extremely high comparing to a standardized extensive Green Roof with a thickness of 4-6 inch (depending on location). Besides the initial costs the lack of water retention (don’t forget all studies are done by the companies!) won’t support any significant bio diversity plus the operational costs (because of the required irrigation) are tremendous over time. Typically these Green Roofs never pay back with they are not utilized for “Green Washing” purposes in advertising.
Irrigated extensive Green Roofs and/or thin layered, super lightweight systems (below 25 lbs/sf) will increase the nutrient pollution in runoff, require higher fertilization application, have hardly any tendency for self-healing, and may increase the pressure of unwanted plants and have a high risk for failure. Irrigated extensive Green Roofs are not environmentally friendly in most loactions!
Green roof designers and green roof professionals must understand that certain advertising, studies, White Papers or project references are all assembled by specific manufacturers and their goal is to make money – unfortunately on the back of a very advanced technology and on the back of their clients.
When we advise our clients they get the full picture because we have seem all solutions in the last 35 years, we have tested them and we are currently working millions of square feet where these systems require upgrades, reinstallation or massive repair (around 20 million in damage so far).
We also help our clients doing it as efficient as possible and to get their money back from prior failures through warranty claims and sophisticated lawsuits. This might help to standardize the function of Green Roofs and helps to get the black sheep out of the market. The building owner has a right that things are done right from the beginning.
Never irrigated in the last 10 years.
Over 15 Million square feet of Green Roofs in 2 days!
In the World’s Green Roof capitol it isn’t a problem to walk over 15 million square feet of Green Roofs in two days.
Grinnell College Students, Architects and Professors joined me this year on a two day trip though out Stuttgart Germany.
Within the city limits and a population of around 700,000, Stuttgart can offer likely over 200 millions square feet of extensive and highly divers Green Roofs – more than the entire USA and probably Canada together.
The two days tour emphasized Green Roofs that are between 15 and 30 years old and that host over 40 different plants species. Remarkable is that not a single Green Roof was ever irrigated, nor fertilized in the last 10-15 years and most of them are maintained only once a year.
No Green Roof was ever replaced or fixed and the water proofing under all Green roofs never, ever leaked (in the US 50% of the green roof are getting fixed or replaced in the first 5 years). The average installation costs were at around $4-6/sf (in the US around $12-18/sf).
All Green Roofs have three major functions: stormwater retention, stormwater retention and stormwater retention.
Green Roofs in Stuttgart are part of a building like windows or doors. There is no necessity to make a big fuss out of it.
Being the World Champion in modern Green Roof technology is nothing to celebrate – it is the responsibility of sustainable and environmental conscious lifestyle combine with common sense.
The highlight of
the tour was the Bosch Parking Garage with the world’s largest Solar
Green Roof that was designed with extremely high diversity of plants
that are found only in (local) native dry meadows.
While the Green Roof measures around ¼ Million square feet the PV is designed for 1 Megawatt.
Unmatched world record in this combination on building structure that is 100 feet above a 6 lane Highway.
Modern Green Roof technology combined with a Blue Roof to minimize artificial irrigation, to maximize water retention and enable visitors to cross a busy four-lane highway without leaving the lush greening of a park.
The Garden Bridge at Universal Studios in Orlando is the first of its kind in Florida. Designed by Miles Architecture Group Inc., Libra Design Group and Green Roof Service LLC, the green bridge creates an innovative connection of Universal City developments. Selected ground covers, shrubs and trees escort pedestrians almost without notice that they are crossing over a busy highway. The distinctive landmark project is engineered with people in mind.
The Garden Bridge at Universal Studios Orlando project is approximately 3,000 sf (145' x between 18 and 25' wide). The bridge is designed to pond water in the granular drainage area to increase the water retention (a blue-green roof combination, Patent hold by Optigreen - 1978 and the first time introduced to North America by Jorg Breuning in 2001).
Unique projects require unique solutions. Keeping the costs for the structure low, the trees are located above the bridge's pillars. The walkway gently winds up to the bridge and over and is easy accessible for the handicapped or service carts.
The project was possible with an outstanding waterproofing solution by ALT Global. ALT Global meets the FLL requirements for root resitance.
This innovative green roof project is a master piece of teamwork between architects, structural engineers, landscape architects and green roof professionals with an open mind, environmental leadership and common sense.
Thank you for all the comments on the blog post:
We believe a lot of people in North America agree with the comment that in some areas Green Roofs can't thrive without irrigation. We at Green Roof Technology don’t disagree nor agree. Allow us to bring the discussion into a fundamental perspective:
Before you built a structure, you have to remove nature or simpler living plants that nobody watered before. Modern green roof technology is able to mimic this type of environment and allows to promote exactly this drought tolerant and hardy vegetation. With a little more understanding of this technology, it is even possible to increase the plant varieties or the plants density.
Nevertheless the attractivity might not meet the expectations of us (humans). Our picture in mind of a roof garden is a lush green vegetation form that is created with plants that please us (humans), that are not poison or dangerous. In some areas we can achieve this goal by utilizing resources that haven’t been available at this location before the structure was built.
By using natural resources (and water is the most valuable) we start changing our environment (we take water away from somewhere – from plants somewhere) just for our own comfort. Understanding that and the value of water should create an awareness to green roof professionals or engineers to design modern green roof technology in a way that no water or super highly restricted amounts of water are utilized.
Unfortunately, the irrigation industry and most of the green roof designers grew up in an environment where resources are endless. With that said the current waste of water on green roofs is simply not acceptable to me and in these cases green roofs are an environmental nightmare - just for our pleasure (and cash) and that things look “nice and green”.
When I drive around in neighborhoods in San Francisco in the morning, my car is being washed by all the sprinklers and nobody has a problem with that…..
Simple and efficient technology is here since many decades but not in the interest of the industry, nor “re-invented” in the US or there is a lack of common sense – maybe it is a combination of all.
Most issues I am confronted with, are a result of high tech irrigation that is just not doing what it is supposed to do, there is not the right app, poorly designed and installed, too complicated for facility people etc. or simply drains the budget of building owners over time this water costs are going up.
Let’s discuss further and email us directly: email@example.com
Comment by Jure Šumi ((LinkedIn):
Interesting input Jorg. Yes, extensive roofs should be self-sufficient where they can be. But in my mind this is not possible in really arid areas like Jim is saying. With our partners in Abu Dhabi we are now investigating what plants should be used there, where top temperatures are regularly reaching 120 F in summer months (with no rain for years). If you use local plants that are surviving in desert than they are surviving only due to the fact that the roots are extremely long and go deep in to the ground to find some moisture (not possible on the roof). Limited irrigation is still needed but the roof needs design with minimised ET, so also irrigation is as low as possible.
Maybe another thing to consider. Yes or no irrigation is also a question of what someone wants from green roof. Nice look is one aspect, stormwater managment is another. We should not forget Energy efficiency. According to our investigation and perfromance tests, evaporation has big effect on energy efficiency in the summer due to cooling effect. If moisture in the green roof system drops below certain level, the cooling effect is limited. So to have best energy perfromance of the roof, than you need irrigation.
Response Jörg Breuning:
Thank you Jure.
My starting point of thoughts about irrigation on extensive green roofs goes back to a fundamental point and only a handful people make these considerations.
Humans are capable to replace nature with a manmade structure on any location on Earth and they make it suitable for people to live there. In these fundamental thoughts, I expect that humans are also able to create this lost part of nature on top of these structures.
I agree this is not always cheap and not everybody is blessed with creativity or experience. Nevertheless, it is possible and it is our responsibility if we respect nature.
The rooting depth of plants is certainly a key element - it isn’t a road block. It seems it is the preferred excuse that we don’t need to feel responsible in what we re doing and that we don’t feel guilty.
I also think it using water for cooling buildings in an open system (what any green roof is) is considered - in my world - using elementary, limited and precious resources for our convenience. In the case that producing water (in dessert states) for the wasteful irrigation of plants (to make our close environment nice) might be a problem to justify to more than 100 million people that have no access to dependable water resources.
What I am saying is, that growing plants even in areas where plants would hardly grow can be done with extremely low impact on natural, precious resources at costs that are lower in the short or long term. The current hype for green roofs can create significant drawbacks in 15 or 20 years from now to building owners if the costs of water continue to rise. Keep in mind a 20 year old green roof is not even the half of the life span of a green roof (at least that is what I know from experience).
Professionals need to start thinking long term and not for quick profit, they should disregard fancy fashions or get away from desperate LEED point collecting terms if they seriously respect nature.
Picture: Deep rooting plant on roof with hardly any soil and never intentially planted (in Texas at the border to Mexico).