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.

Solar and Green Roof with Green Roof Plants

News-brief from Environmental Building News

Green Roofs Improve Solar Panel Efficiency 

By Erin Weaver 

Green roofs are known to extend roof life, conserve energy, and reduce stormwater runoff and air pollution; new studies show they can also boost the performance of solar panels. Plants reduce a roof’s contribution to the urban heat-island effect by lowering the surrounding air temperature through evaporation; this cooling can also make photovoltaic panels perform more efficiently. Plants also reduce airborne pollutants and dust particles, allowing the panels to absorb more sunlight. 

Studies vary in the efficiency boosts reported, from 3% to 16%. This is in addition to green roofs’ known effect of cooling indoor air, which reduces annual energy use by 6%, according to a recent French study. 

New designs for solar arrays allow water to drain evenly across the roof, and research suggests that the biodiversity created by including shade-tolerant plants below the panels can improve a green roof’s overall performance. A recent British study in Building and Environment found that broad-leafed plants such as lamb’s ear, which can thrive in partial shade, outperformed the traditional sedum in cooling the substrate and surrounding air. 

 

December 1, 2012

---

DISCUSSIONS, Comments

Reader-contributed comments related to Green Roofs Improve Solar Panel Effciency - EBN: 21:12. Comments are listed with newest at the top.

Green Roof Plants Posted by Jorg Breuning on Dec 2, 2012, 06:12 PM  
 
Sedums are a large genus of flowering plants commonly known as stonecrops. They are found worldwide from tropical regions to the Polar Circle. There are more than 400 different Sedum species known and most of them survive in locations that have hardly soil. The survive-ability of Sedums under extreme conditions with a thin layer of soil and almost endless varieties makes them to the ideal, perennial ground-cover for extensive green roofs.

The British study over less than two years with broad-leafed perennials like (mentioned Stachys byzantina, Bergenia cordifolia and Hedera hibernica) require deeper soil profiles. More green roof growing media (soil) increases the costs of the green roof, the structure and the maintenance dramatically and so decrease the likelihood of having a green roof to start with. Comparing Sedums with the mentioned type of perennials is like comparing wild strawberries with apples.

The readers of this Solar/Green Roof (Sun-Root)article also must understand that the climate conditions in Great Britain are unique and generously supported with moderate temperatures by the golf stream all year around.

As a green roof expert with over 40 years of experience I can clearly say that this research is worthless and proves only common sense. If this study would have been done by experienced researches the plant selection would have considered broad-leafed, perennial plants that grow in the same conditions as the compared Sedums.
In modern green roof technology there are multiple choices of herbaceous perennial plants that supplement the fundamental Sedum carpet.

Learn more about Solar Garden Roof or "Biosolar"

 

Green Roof Technology

Green Roof Service LLC – with more than a quarter century of experience as leaders in the establishment of the green roof industry in German spoken Europe and Great Britain, the principals have actively designed, installed, monitored and perfected their craft. Having been involved with millions of square footage of green roof projects, their understanding of these systems is unsurpassed. As they have no allegiance to any specific product manufacturer, they select the materials and approaches that work best in any given circumstance.

The principals participated in the largest research green roof endeavour ever undertaken (at Optigrün International AG in Germany, begun in 1994/1995, still ongoing) and have access to the resulting data (not fully translated into English) and an intimate knowledge of the “behind the scenes” circumstances that affect data output. Having one of the largest libraries for green roof research and products in the US, they continually update their resources and knowledge of ongoing research and new projects even when they are done by others.

The unmatched experience of the principals, acknowledged by the German FLL e.V. the FBB/EFB (German/ European Green Roof Association) and the German Landscape Association (GALA-BAU e.V) brought them in 1999 to the United States of America. The City of Chicago was the first project in the US which was built according modern Green Roof technology and starting with this project the principals were able to promote, educate and train today’s and nation’s key-player in the green roof industry.

The founders of Green Roof Service LLC understand modern Green Roof technology which is the basis for successful projects. They also understand related roofing details and the execution of highly skilled on-site monitoring which makes the green roof reliable and lasting as long as the building itself.

The experience of 120 Millions square foot of annual new Green Roof construction in Germany, with all ordinary and extra ordinary solutions, with all the competitiveness and all the efficiency is represented by Green Roof Service LLC in the United States of America.
Their extensive background affords them the right to boast the ability to ensure the outcome of each project they tackle.