By: Samantha Yurek
Photo Credit: Flickr - Sidstamm
By: Samantha Yurek
Photo Credit: Flickr - Sidstamm
By: Samantha Yurek
With the heat index well into the triple digits lately, it is only appropriate to talk about the urban heat island. A metropolitan area which is significantly warmer than its rural counterparts, the urban heat island effect creates a more brutal environment, especially during these sweltering summer days.
Cities are dense and compact places. Most surface materials in urban spaces are good at absorbing heat, and have no means to transpire. Sunlight heats up these surfaces during the daytime, to temperatures higher than the air. In addition, impervious surfaces are prominent in city landscapes.
Many issues stem from the urban heat island effect, including increased energy consumption, resulting in elevated pollution emissions, compromising human health and comfort. Also, hotter surfaces create warmer runoff, endangering the local bodies of water; rapid temperature changes can be fatal for aquatic life.
Photo Credit: Dustin Phillips
Now we understand the urban heat island phenomenon, but is it easily resolved?
Unfortunately with the amount of people residing in urban areas, the energy released will always be greater compared to rural areas. Although, there are ways to mitigate the hotter temperatures. In rural areas, temperatures are moderated through evapotranspiration, with vegetation being the main aid in cooler and healthier environments. According to the Environmental Protection Agency, "Trees, vegetation and green roofs can reduce heating and cooling energy use and associated air pollution and greenhouse gas emissions, remove air pollutants, sequester and store carbon, help lower the risk of heat-related illnesses and deaths, improve stormwater control and water quality, reduce noise levels, create habitats, improve aesthetic qualities, and increase property values."
By increasing vegetation in urban areas and the surrounding commercial belts in the form of street trees and green roofs, we can help create a cooler and healthier environment for ourselves. Not to mention a much more attractive landscape.
The issue of root penetration is known to most in the green roofing industry. The relatively complex world of roofing membrane compounds and organic chemistry has resulted in most green roof professionals defaulting to local instructional manuals, which default to FLL testing records. But just because a material is effective does not mean it is not harmful, e.g. lead in paint.
In 1997, Bayer Aktiengesellschaft was the assignee of Patent US 5672568 A titled “Root growth inhibitors for building materials comprising monohydric alcohol esters of mecoprop.” Root-resistant bitumen mixtures were soon marketed.
This past week the Berlin Senate’s Department for Urban Development and Environment and the Berlin State Office for Health and Social Affair published a series of recommendations for the prevention of environmental pollution due to the release of the herbicide Mecoprop from root-resistant bitumen membrane sheets.
The statement reads:
Investigations at the Swiss Federal Institute for Water Resource and Conservation (EAWAG) on behalf of the Swiss Federal Office for the Environment (FOEN) have shown that Mecoprop under natural weather exposure is released from the bitumen sheets and the precipitate is washed out.
Rain water contaminated with Mecoprop can pollute combined sewers or surface waters. Due to the low rate of elimination in sewage treatment plants results in a particularly high risk potential. In a decentralized rainwater infiltration system there is a risk of soil and groundwater contamination. (Translated from the German)
The report goes on to make simple recommendations. The first says the use of bituminous membranes impregnated with Mecoprop should not be used unless absolutely necessary for structural reasons. Second, they should never be used in protected water areas.
Green Roof Technology is against any use of herbicides in green roof construction or maintenance. For more information on how to protect your building against root penetration without the use of poisonous herbicides please contact our office.
On July 9th, three more small extensive green roofs were installed a top the Academy’s High School Building in Newtown Square, PA. The High School has a number of glass walled hallways that look out over unsightly black rooftops. The glass walled hallways provide a spectacular viewing area for the green roofs. This year we covered almost three times as much roof area as we did last year, bring the Academy’s total green roof count to five.
Once again, Micah from Urban Ecoforms joined us to lend his experienced hand at installing green roofs. From the picture below you can see that Micah was in rare form and simply thrilled to be freed from his recent solitary confinement atop his current project in West Philly.
While we were installing the green roofs, we could not help but stop and admire the incredible lushness of the green roofs we installed last summer, especially when last July was brutally hot and dry.
An Executive Summary of Facts by Jörg Breuning
It is unavoidable and common sense that wearing wet clothes in winter will end up in hypothermia. Wearing the same wet clothes on a hot summer day, might actually help to feel cooler - not to be confused with feeling more comfortable. If we have only one set of clothes, for all four seasons, they would typically be made up of two layers. The first layer protects against direct environmental impacts such as sunlight, rain or wind and the second layer usually consists of a breathable layer for comfortable wearing and controlled air circulation.
I have learned on my travels all across different desserts on earth that these layers reduce temperature increase on hot, sunny days, but at the same time can reduce the loss of body heat during extremely cold nights. Indigenous people of extreme environments have learned this lesson over centuries and were able to survive under these circumstances with this simple layer strategy. My father always used to say: "What is good for the cold is also good for the warm."
Any man-made structure is nothing more than a body that requires consistent 'body temperature' to make it usable for the purposed design. A building without reliable all-season clothes is worthless or requires a tremendous effort (energy or operating costs) to make it useful.
Helping to make a building useful for people, the 'coat' consists typically of an insulation layer covered with a layer to protect against the elements (waterproofing, roofing membrane). Since we all know that the protective sheet will deteriorate over time this sheet (waterproofing) has to eventually be renewed, a process experts call re-roofing, which usually happens every 18-25 years.
It is proven by my experience (since I have been designing and installing green roofs for 35 years) that a green roof can double the lifespan of the roof. The green roof acts like an additional all season two-layer system on top of the roof where healthy plants are the first layer, protecting against direct environmental impacts. The green roof growing media (green roof soil) is the breathable layer.
There is only one difference; the breathable layer (growing media) on a green roof is also the basis for the well-being of the plants and must be able to store water and air at the same time for a healthy growth. If this layer doesn't fully support the plants (and only the plants) the entire coat does not function and the plants tend to indicate this by suffering or a change in plant varieties present.
Above we learned that a wet coat in winter causes problems because water is not a good insulator and so we have to consider heat loss in winter when speaking about green roofs. We also understand now that dry green roof soil in summer will store heat (in the aggregates) and increases the cooling needs.
A green roof (and green walls that grow on growing substrates on vertical surfaces with consistent irrigation) are only thermal masses with hardly any insulating values. Considering these facts, building owners should be cautious when someone tells them that green roofs are good insulators. This is just not the case, especially if the building envelope is not insulated correctly in the beginning. Fixing heating and cooling loss simply through green roofs and/or green walls is impossible or a short-term solution.
With all the current research in this field, it's surprising to me that people still claim green roofs are good insulators. Additional insulation below the original coat is necessary (waterproofing or walls) to make the most effective roof (cost wise and physically) compared to any vegetated layer combined with growing media of growing substrate.
However, the thermal mass "green roof" certainly has lifespan extending properties for the waterproofing (and again, I can confirm this with projects spanning over 35 years). This is the key to start thinking in long terms (50+ years) in the building industry and is the most sustainable approach. Longevity is hardly considered in LEED™ certifications and with less emphasis on longevity, many awarded LEED™ buildings might fail for a certification because they can't be upgraded easily when the costs of energy increase. I am not referring to how wasteful the footprints of many of these 'innovative' building designs are.
Photo DM Products: Penn State's futuristic Millennium Science Complex earns LEED Gold for this space-wasting empty over hang. The 'water head' of the campus (or of their bureaucracy). Pants can not even grow underneath - how can people survive?
In the last 35 years, energy costs increased eight to ten times (!) and are expected to grow accordingly over the next three to five decades (or the lifespan of a green roof). Knowing this, selling a green roof for insulation purposes will unavoidably end up in a costly disaster for the building owner. Removing a fully functioning green roof in less that 25 years after installation, simply to add to more insulation, meet future requirements or to keep heating and cooling costs low.
Green roofs do not extend the life span of selected, important building components dramatically. Increasing the lifespan of any building is the best environmentally friendly approach in the building industry and the most efficient way to reduce costs for the owner over decades. Although, if scientitst and green roof professionals often do not understand this unique property of green roofs and don't design underplaying components accordingly, the building owner won't be very happy in the future. In 20-25 years when parts star needing to be replaced, a second green roof will be the last choice of the building owner because it will simply be additional costs with few benefits as originally promoted.He might not understand why he should disassemble a perfectly functioning and well established green roof, precisely when certain individuals led him in the wrong direction in the past.
• As a building owner be careful when people try to sell you green roofs as a good insulator without mentioning that additional insulation is necessary for the building for future energy needs.
• Building owners have to understand that any available research about the insulation value of green roofs reflect only a current snap shot and potential savings in a very short time period (less that half life time of a green roof) and they are worthless when the intention is to build for half a century.
• There are no energy studies completed over a 50+ year time span comparing a green roof (plus additional insulation) and a conventional roof that will be re-roofed with additional insulation 20 years from now (typical re-roofing practice)
Trust only experts that recommend additional insulation under the green roof because then they expect that your investment will last a human lifetime, which will be profitable but also affordable during this time. Designing the roof (or wall) to last for five decades or more requires a lot of responsibility and expertise of the designers - if they value their customers.
By: Jörg Breuning
Extensive green roofs are a thin layer of high performance components that allow a wide range of plants to grow on them. These plants have adapted over thousands of years to extremely harsh environments and are typically found in alpine regions, on natural rock debris (scree), deserts or tundra. Besides the extreme climate conditions in these areas, there is a very inconsistent supply of water or lack of water retention because of missing components in the soil (no fines, no organic).
In other words, these are typically locations where plants have to be very specialized. Once they have adapted, they are awarded by less competition of other plants - plants that require deeper, richer soils with a fine granular distribution line or high organic content.
Plants from these extreme conditions have not learned to compete with plants that we typically prefer for our gardens or our farms. Experienced horticulturists and plant collectors understand very well what it takes to grow these survivors, in locations other than their natural habitat. These experts are able to create an environment that supports these plants to prosper. These man-made environments are an example of modern green roof technology via extensive green roofs. Natural coarse, porous aggregates (pumice, lava rock) prove to be the most successful way to accomplish a proper environment. The porosity of the materials allows high water retention with simultaneously high air content. Also, this can be done very inexpensively and on a large scale. Modern green roof technology is engineered to ensure that every raindrop will penetrate the this soil layer immediately - soils with high organic content take too long for water to penetrate, resulting in standing water and consequently erosion.
Some people may try to get around some of nature's principals, essentially reinventing the wheel in regards of extensive green roofs. They may also try and maximize other potential benefits (including personal profits), but end up sacrificing something else and in the worst case plants will suffer and possibly die.
The plants, whether they were intentionally planted or not, are an indicator for the performance of any green roof system. If any extensive green roof system becomes high maintenance, requiring irrigation or extra nutrients, the whole purpose of the green roof is defeated. Understanding these complex synergetic effects don't take a PhD, green roof professional training, or the internet - it takes decades of experience in the field, the patience of gardeners and common sense.
Modern green roof technology - as described in the FLL guideline - combines all these decades of experiences and makes things as simple as possible for novice green roof applicators - but it sure doesn't try to simplify the process. Einstein had some good advice on the subject, "Make things as simple as possible, but not simpler."
Jörg Breuning welcomes people who want to learn from decades of green roof experience - firstname.lastname@example.org
By: Jörg Breuning
Information spreads like wildfire in today's world; between the internet and numerous social media sites. It has become extremely easy to access relevant information anytime, anywhere. This is a fantastic technological advancement, with one weakness. Anyone can "publish" anything.
Since the internet makes everything very easy to spread any kind of information around the globe in seconds, it seems that the quality of information provided to the public dropped at accordingly the same speed as it's distribution. Some people jump to conclusions; they are quick to talk and other are quick to responds via text and in most cases these are not the same people. I get the impression that one group is too lazy to write and the other group too lazy to think. They have a desperate need for attention - I like to call it Recognition Deficit or RD for short, which unfortunately results in misleading and false information to the reader. Many people in the audience often find it necessary to then add their own opinions and re-post the article, making things even worse.
An excellent example of RD was recently posted in the American Scientific. I believe this certainly affected their reputation in the scientific world and hopefully leads to better supervision of the people who have permission to post. Their article was copied and pasted onto numerous other websites, regardless of the comments left on the original page. In this instance, RD wasn't the only symptom, a combination of ignorance and laziness was also thrown into the mix.
Modern green roof technology is a well-established technology around the world. If some researchers think that there is room for improvements, they should consider previous research from around the world in addition to what might be sacrificed along the way. Focusing on one aspect of the issue won't work in a complex ecosystem. There are no defining traits of complex ecosystems, where Mother Nature undergoes consistent changes. Having a tunnel view sometimes helps, however we can't afford to lose the bird's-eye perspective of the decades of experience and hands-on professionals.
To all the skeptics out there, let's make a long story short:
Green Roofs do work, but many people don't!
By: Rebecca Gullott
Not many Marylanders are happy about paying the new stormwater fee or “rain tax” as it has come to be known. The county imposed fee is based on the amount of impervious surface such as rooftops and driveways on each property (cost-by-cause principle). In Howard County alone there are over 19,000 acres of impervious surfaces that contribute to pollution of local streams and the Chesapeake Bay. 19,000 acres are almost 30 sq miles or 11% of the counties size- more than double the size of all water ways in the county! No wonder that Stormwater runoff is responsible for over 20% of pollution into the bay.
Those wishing to lessen their stormwater fee can reduce the impervious surface area on their property through smart design and management practices. Howard County is providing instruction and incentives for citizens to do just that. Howard County Stormwater Management Division has partnered with several organizations including the University of Maryland Extension to help citizens take control of their environmental impact. Rainscaping workshops will be offered this summer to show residents how to plant and maintain rain gardens and native species; as well as compost waste and use rain barrels to collect roof runoff for use in lawn and garden irrigation or car washing. Howard County is offering free rain barrels at the Alpha Ridge Landfill select Saturdays April through September. Other Maryland Counties have similar programs so check your county’s website to see what offerings are available.
Property owners can receive credits for on-site improvements that reduce impervious surfaces. Whether it’s establishing a rain garden in the yard or incorporating planted areas or green roofs into the company’s parking lot, these incentives may encourage citizens to take control of their environmental impacts. These changes may help to reduce the need for future stormwater fee increases and promote a healthier Chesapeake for years to come.
The possitive impact for the environment by implementing cost-by-cause fess is very effective in many other counties and States in the US and over decades in Europe.
Green Roofs and Native Organisms
It is all about perspectives, experience and evolution. Any organism has a right to exist. It is the intention of each organism to multiply, spread and adjust to the surrounding environmental conditions. This adamant approach has also helped humans to develop and thrive over ten thousands of years. The word native has become a stereotype of certain organisms like plants that should be growing only in a particular region – that is what humans think.
Exceptions seem only allowed with human approval and when they support human development – this is one reason why nobody has a problem with Gen manipulated corn for “bio fuel”. When our ideal of a functional environment gets out of balance there is always a solution from clever people with a weapon (solution) allegedly reversing the discovered issues. Sometimes an issue has to be created first to offer a solution to gain some popularity and attention. A few of them are even henchmen for big companies that intend to increase sales for an existing product in a new market. The system works in all levels but it is questionable when I see these paramilitary battles on TV commercials against a dandelion (Taraxacum officinale) what is a “native” plant and it is clearly classified as a beneficial weed.
By: Samantha Yurek
Honey bees are the most significant pollinators on earth. They are responsible for pollinating approximately 80% of our flowering crops. "If the bee disappeared off the surface of the globe, then man would only have four years of life left." It may be questionable to whether this quote came directly from Albert Einstein himself, but it is indisputable that the honeybee population is essential for maintaining the quality of life we enjoy so much.
Yesterday, the European Union stood up for the honeybees and banned a group of potent pesticides classified as neonicotinoids. Neonicotinoids are commonly used to prevent pests on plants such as soy, corn, canola, sugar and wheat. Evidence has surfaced that these pesticides are responsible for the honeybee decline or Colony Collapse Disorder, a phenomenon that appeared in 2006. Neonicotinoids are known to agitate the honeybee's reproduction processes, communication and navigation skills, along with weakening their immune systems.
We take pride in avoiding herbicides and pesticides at Green Roof Technology. A green roof is an excellent habitat for all pollinators, especially honeybees. Watch a video about beehives on rooftops in Baltimore or learn about the plants you may choose specifically to lure these fuzzy creatures to your green roof!
Photo Credit: Green Roof Technology