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What is Mineral Wool?

Mineral wool, mineral fibers, or man-made mineral fibers are products made from natural or synthetic minerals. The term "man-made mineral fibers" is generally used to refer solely to synthetic materials including fiberglass, ceramic fibers and stone wool. Since their first commercial production in 1871 (Georgmarienhütte, Osnabrück, Germany), mineral wool found its way in many applications such as thermal insulation (as both structural insulation and pipe insulation), and soundproofing. Patents in this regard date back to the 1930’s. The hydrophobic properties of mineral wool make it ideal for building products.


Much later hydrophilic mineral wool was developed for fully controlled horticultural purposes like germination of seedlings or simple hydroponic systems for vegetables (Fertigation).

Hydrophilic mineral wool has very high water retention so it was no surprise that this specially prepared mineral wool came to the attention of the German Green Roof industry in 1985. International patents from 1986 and later in 1990 by Gruenzweig + Hartman (one of the largest mineral wool manufacturer in the world) document their involvement with the Green Roof industry.


History of Mineral Wool in Green Roofs

Unlike the North America, where new components and materials flood the Green Roof market with little or no research, Gruenzweig + Hartman made extensive tests over more than 5 years at one of the most recognized University for Green Roof research in Germany. All this was done before their scheduled introduction to the booming Green Roof market in Germany.

The first publications about mineral wool in lightweight Green Roof systems were finally available in May 2001 (Dach + Grün 2/2001). The tests (almost a decade long) revealed results that where shattering the big expectations like a piece of glass that falls on the ground. Without doubt the Mineral Wool has advantages in germinating vegetation but in the medium-run or long-run any traditional Green Roof (according FLL) will outperform a system containing Mineral Wool.

As a consequence Gruenzweig + Hartman stepped out of this segment of horticulture. With them the world’s largest Green Roof component supplies (like Optigreen AG and Zinco and others) declared this technology as not useful for modern Green Roof technology - until today. Actually many on these early Green Roofs were replaced and the current market share of these systems in Europe is approximately below 0.01% of all Green Roofs.

Mineral Wool possesses excellent properties for the building industry as insulation material and it might has a limited place in commercial horticulture for vegetables in Greenhouses.

For the modern Green Roof industry, however, this material lacks in performance, it is too expensive, requires project customized engineering and has very high operational costs. Against all marketing materials that exists in the English language: Mineral Wool in Green Roofs was and is factually never successful and has only a poor track record over the last 30 years.

In fundamental horticultural knowledge for Green Roofs, Living Roofs, Eco Roofs, Vegetated Roofs or simple of vegetation on impervious surfaces North America is still 20 years behind the European expertise. Since 1999 Green Roof Service LLC - Green Roof Technology ongoing efforts in North America shall close this gap with common sense and the ability to make Green Roofs as popular, as economic, ecologic and sustaining as in Europe.

Our clients don’t have headaches and we don't use our clients as a Guinean pig.


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