Wood wool lightweight panel

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Wood wool lightweight panel
HWL surface structure
HWL surface structure
raw materials Cement or magnesite; Wood
Primary energy consumption (production) 35 kWh / m³
Material properties
Thermal conductivity  λ 0.093 W / (m K)
Bulk density ρ 360 kg / m³
Vapor diffusion resistance  μ 2-5
Areas of application Wall, ceiling (in connection with plaster base ); Acoustic panel
Logo of the German Institute for Standardization DIN EN 13168
Area building technology
title Thermal insulation products for buildings - Factory made wood wool (WW) products
Latest edition 2015-04

Wood wool lightweight panels (also known as HWL panels ) are construction panels made of long-fiber wood wool and mineral-based binding agents . HWL panels are used as plasterable insulation panels in the interior and exterior. Colloquially, they are often referred to as "sauerkraut platters" or "sauerkohl platters". Brand names - partly historical - are u. a. Ceban, Erulit, Fibrolith, Frankotekt, Hapec, Hapri, Heraklith , Hincolith, Klimalit, Lenzolite, Lignolith and Saalith.

Because of the term “wool”, laypeople sometimes confuse them with the significantly more heat-insulating, but without mineral binders and completely differently structured wood fiber insulation boards .


HWL panels have been standardized in DIN 1101 since 1938 and are therefore among the oldest technically manufactured insulation materials made from renewable raw materials . The standard was withdrawn in March 2007 and replaced by the European standard EN 13168 and the DIN standard DIN V 4108-10.

Materials and manufacture

Softwood, especially spruce and pine , as well as cement or caustic burned magnesite (magnesium oxide, Sorel cement) are used as binders for HWL panels and also for wood wool layers in composite panels . Panels bound with magnesite can be recognized by their beige color, whereas products with gray cement as a binding agent have a gray color. White cement is also used to maintain the natural tone of the wood.

After the wood has dried , it is planed into long fibers in wood wool machines. The fibers are then mixed in a mixer with the binding agent made from caustic-burned magnesite or cement. This raw material is then fed into an insert molding strand in order to be shaped according to the panel format and thickness.

After pre-pressing, the material is cut between the individual shapes using a saw. The filled forms are then stacked, pressed again in stacks and loaded so that form lies flush with form. After the drying time, the stacks of panels are removed, dried again and cut to the required size.

The production takes place according to EN 13168.

Properties and uses

Wood wool lightweight panel as a window reveal

Wood wool lightweight panels are dimensionally stable and very strong. Their thermal insulation ability is low (0.093 W / (m · K) compared to approx. 0.04 W / (m · K) with standard insulation materials), while the heat capacity and thus the summer heat protection are high. Further strengths of the wood wool lightweight board are good sound insulation (plastered) or sound absorption (unplastered) and moisture regulation ability.

They are considered flame retardant (fire protection class B1). HW panels are used primarily as a plaster base for ceiling or roof soffits and as acoustic panels for sound insulation. In masonry and concrete construction , they are used to insulate components with good thermal conductivity, as plaster bases and acoustic panels, in wood construction as plaster bases or for cladding indoors or outdoors.

Multi-layer lightweight panel

The multi-layer lightweight board (ML board) is a combination of the wood wool lightweight board with rigid foam (HS-ML boards) or mineral fiber (Min-ML board) as insulation. In accordance with the higher insulation effect of the mineral or synthetic insulation materials, up to twice as high insulation values ​​are achieved as with the pure wood wool lightweight board.

The panels are offered in three or two layers. With a three-layer structure, the additional insulation layer is embedded between the two outer layers made of mineral-bound wood wool. The rigid foam layer consists of polystyrene particle foam ; if a mineral fiber layer is used, the fibers are arranged perpendicular to the plate surface. The thickness of the wood wool layers is at least 5 mm.

During the shaping of the ML board, a wood wool binding agent fleece is sprinkled into the molding strand. Then the prefabricated polystyrene particle foam or mineral fiber board is fed between two raw material shafts via a multi-layer system. For the ML three-layer board, the upper wood wool binding agent fleece is then applied via the second raw manhole.

In contrast to pure wood wool lightweight panels, the disposal of the ML panels is more complex, since the composite panels can hardly be disposed of.

See also

Individual evidence

  1. Information on the Fibrolith brand  in the register of the German Patent and Trademark Office (DPMA)
  2. Information on the Hapri brand  in the register of the German Patent and Trademark Office (DPMA)
  3. Information on the Heraklith trademark  in the register of the German Patent and Trademark Office (DPMA)
  4. F. Kollmann: Hardened woods and wood-containing building materials and materials. Terms and symbols. Explanations of the standard sheet DIN 4076. Springer-Verlag, Berlin, Heidelberg 1942, p. 41–59 (Special print made of wood as raw and material 1942, 5th year, issue 2/3).
  5. a b Agency for Renewable Raw Materials e. V. (Ed.): Insulation materials from renewable raw materials . 2nd Edition. 2008, p. 24–27 (here p. 24).
  6. Ingo Gabriel, Heinz Ladener (ed.): From old buildings to low-energy and passive houses . Ökobuch-Verlag, Staufen near Freiburg 2008, ISBN 978-3-936896-32-9 , p. 74-75 .
  7. waermedaemmstoffe.com accessed on August 5, 2009, again on May 5, 2010.