Green Roof Innovation
Green Roof Technology Reveals Latest Study about Mineral Wool on Living
Since
their first commercial production in 1871 (Georgmarienhütte, Germany), mineral
wool found its way in many applications like thermal insulation and soundproofing. 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.
Doing it right in the first place.
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