Mineral Wool on Green Roofs

Green Roof Innovation

Mineral Wool on Green Roofs – Chance or Challenge? 

Green Roof Technology Reveals Latest Study about Mineral Wool on Living Roofs

Since their first commercial production in 1871 (Georgmarienhütte, Germany), mineral wool found its way in many applications like thermal insulation andsoundproofing. Mineral wool, mineral fibers are typically referred to synthetic materials like fiber glass, ceramic fibers and stone or rock wool. 

Two main types of mineral wools are on the market – water repellent (Hydrophobic) and water adsorbent (Hydrophilic). For horticultural purposes, only the hydrophilic type is useful. Many patents were granted for simple Hydroponic systems or the germination of seeds with mineral wool in the early 80’s.

In modern green roof technology the first green roof systems came on the market around 1985 in Germany at a time as the German green roof industry gained tremendous momentum. As a lightweight solution with high water retention, mineral wool seemed an ideal material. The higher costs and the higher carbon footprint - comparing to lightweight aggregates – were argued with easier installation and higher water retention.

Extensive research over more than 5 years at the University of Geisenheim and on numerous buildings confirmed the high water retention properties. However, in the mid-run these tests also revealed that the performance and the health of the vegetation were far below conventional green roof systems with standardize green roof components. Mineral wool manufacturers and green roof system suppliers stepped away from the idea of using mineral wool as a growing component for green roofs.

“Today we can see a revival of mineral wools in the green roof industry,” says Jorg Breuning, CEO, Green Roof Service LLC,” in countries with hardly any green roof experience, mineral wool is getting rather popular with potentially fatal results in the mid and long-run.”

Especially in the United States, the market is growing rapidly for mineral wools on green roofs, disregarding existing studies and without extensive long-term tests. It isn’t even proven whether certain fibers can cause health problems, leach out chemicals or whether these components can be recycled when the green roof doesn’t perform anymore.

In 2012, the lack of performance of mineral wool as a vegetation carrier resulted in a major green roof restoration at Amsterdam International Airport. 90,000 square foot of green roof – built with mineral wool - had been taken off and replaced by a standardized green roof system. At this point, this was the largest green roof restoration in the history of mineral wool on green roofs. Costs that could have been avoided.

Read entire study at Green Roof Service LLC /Green Roof Technology or at Scribd

Doing it right in the first place.

Only Natives on Green Roofs?

Only Natives on Green Roofs?

In 1999 North America discovered that modern green roof technology is more than just an exclusive garden for a few wealthy people on top of a building. Experts understood very quickly that there are unmatched advantages of bringing back nature into locations where it was before. 

With this enthusiasm, a lot of environmentalists and environmental organizations started to notice various opportunities to improve, simplify or promote themselves in many ways. Some of these ideas might sound glamorous, but the bigger picture of nature, is often disregarded.

 

In other blog posts we reported about the ridiculous reductionist research of comparing reflective roofs with green roofs. Today we want to focus on the hype of native plants for green roofs:

 

Many Americans call a living organism native if these organisms have been on this continent before North America was discovered by European settlers. In their naivety, they have completely forgotten how the natives have discovered and have lived on the land hundreds to thousands of years before.

So called Native people did the same as any organism; they expanded from their original locations to secure the species. While migrating and expanding over continents, all living organisms will change the environment accordingly. From micro organisms to macro organisms (including humans) all life undergoes evolution. The migration of European settlers did that as well and eventually became "native" and naive at the same time.

For most American people (as mentioned on English Wikipedia) the opposite of native is "invasive". This is ignorance and discrimination against natural migrations. It is even a bigger discrimination and ignorance of God's creation or evolution (whatever you prefer) when the same people (a lot of them call themselves experts) tell us that approximately 1,000 hectares of Bamboo scattered across the USA are a problem and at the same time 1,000,000 hectares (1,000 times more) of genetically modified corn is not a problem. On top of this blatant discrimination, these 'tunnel-view' educated people (including LEED™) are pointing out that roofs are an ideal place for what they deem native plants.

Rooftops might be a stepping stone environment for plants that have been in North America for many thousands of years. However,  when we try and set them up in a new place it is like a conversation of a narrowed down selection of species and disregarding the entire picture, climate change, and denying natural changes as a foundation of our existences. It is obvious that history repeats itself - as European settlers came to the Americas they exploited all resources, removed and relocated native humans, introduced a new human specie as forced laborers, and brought their on living elements to replicated the land they left. The better a specie "served" these settlers the higher the chance to travel with them to new places. For over 100s of Million years, species have learned to look for travel opportunists to spread further. 

  

Green roofs are ground remote and artificial environments in the first place. Most native plants are not used to such a "new" location. Green Roofs also don't allow required natural players (other living organisms) to thrive there - or "we" don't want them there because of our selective thinking.

For example: 

• Jeffersonia diphylla depends on ants to spread and what building owners want to have colonies of ants?
• The big family of Trifolium (stamped as a weed by nurseries) requires the stiff hair of animals to fulfill their natural calling - how many deer of bears do you want on your roof?
• Or how can we control birds (native or introduced) from spreading seeds?

The simple point of this blog is: Any type of plant is better than an impervious surface like asphalt, concrete or excessive, nicely manicured lawns. Our environmental issues are caused by the loss of vegetation. It would be more effective to further protect natural environments instead of creating plant-only reservations on rooftops. Human life fully depends on vegetation, actually we evolved from vegetation. Trying to select good or bad makes our specie disappear faster than we came because the history of plants on Earth is around 2,000 times older than our and they continue their journey of evolution even after us.