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Leaf particles from the Typha wetland plant can be used to produce stable thermal insulation boards.
© typha technik Naturbaustoffe
Sustainable thermal insulation

The industrial partner Saint Gobain Isover is planning to market the Typha on-roof thermal insulation.
© Fraunhofer-Institut für Bauphysik

The Typha leaves consist of fibre-reinforced connective tissue filled with soft, open-cell sponge tissue.
© typha technik Naturbaustoffe

On-roof insulation made of cattail plants in development

Energy-saving in the production, pressure-resistant and compostable: Researchers at the Fraunhofer Institute for Building Physics have high expectations for the insulation boards made from the leaves of the Typha plant. Together with industrial partner Saint Gobain Isover, they are now further developing a board for insulating rafters and preparing its series production.

The use of cattail (Typha) as a raw material for producing building material combines advantages in the plant cultivation, manufacturing process and board properties. The Fraunhofer Institute for Building Physics IBP and typha technik already developed a building board made of cattail several years ago. “The magnesite-bonded Typha board offers good strength and flexural stiffness with low thermal conductivity. For example, it is already being successfully used in restoring half-timbered buildings,” reports Professor Martin Krus from Fraunhofer IBP in Holzkirchen. “Based on this experience we are now working on a comparable product for on-roof thermal insulation. For this application the bulk density needs to be reduced and the insulating effect further increased.” Saint Gobain Isover, an experienced partner in producing thermal insulation, has also joined the recently started research project and aims to subsequently launch the product on the market.

In addition to its insulating effect and pressure resistance, the Typha board impresses with good summer-time thermal insulation and sound insulation. It is relatively permeable and capillary active. In terms of fire protection, it is clearly superior to wood fibreboards: similar to magnesite-bonded Typha board, it has – though to a slightly lesser extent – a high fire resistance due to its Typha and magnesite constituents, and unlike wood fibreboard it does not smoulder. Another big plus point is the possibility to recycle the boards at the end of their service lives without any problems, i.e. to be able to compost them (cradle to cradle principle).

Renewable resource

The hardy Typha wetland plant grows in natural pure stands and can be found worldwide. Its leaves consist of fibre-reinforced connective tissue filled with soft, open-cell sponge tissue. The manufacture from leaf particles transfers these positive plant properties to the product and gives it stability and a good thermal insulating effect. The high content of polyphenols in Typha plants makes them resistant to fungal and insect infestation. The narrow-leaved cattail (Typha angustifolia) used for producing Typha boards forms extremely dense stands up to 3 metres high. This produces 15 to 20 tonnes of dry raw material per hectare – four to five times as much as coniferous forests in Germany produce. From this, about 150-250 m3 of the newly developed building material can be produced annually.

The fact that Typha grows well across suitable areas has already been demonstrated by a project supported by the German Federal Environmental Foundation. The new research project is being funded by the German Federal Ministry for Economic Affairs and Energy.

You can find a detailed version of this news item on the ENERGIEWENDEBAUEN web portal.



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Project management
Fraunhofer IBP

Material-based investigations, demonstration building