Hiss Reet Panels as Inside Insulation for a Timbered House
Due to their good diffusion properties, their excellent price-performance ratio and their natural composition reed panels are perfectly suitable for the insulation of buildings. Reed insulation panels combined with clay offer an insulation system which has proven its worth over the years. Thanks to their coarse texture the reed insulation panels can serve as a plaster base at the same time.
From an ecological and point of view and with regards to building biology the renovation of an office building should make particular use of the historic building materials clay and reed. After gutting the building an inside insulation with reed panels was installed in order to preserve the façade of the timbered house. All non-bearing interior walls were built using Hiss Reet walls.
The Hiss Reet panels have been fitted following these four steps:
1. The old timbered house which had gypsum plastered walls was gutted and the gypsum plaster removed. Internal vapour barriers were avoided in the installation of the inside insulation from reed panels. All vapour retarding layers were removed from the inner side of the exterior walls. The timber beams, some of which were heavily affected by rot, were mended.
Illustration 1: A gutted part of the building with mended timber beams.
Built in the 1930s, this building served as accommodation for workers of the German Railways. Until its destruction in World War II it had been a „pure” timbered house. The parts of the building which were destroyed have been rebuilt in double-shell masonry. Even then, reed screens where used as plaster fabric.
2. The reed insulation panels were glued to the exterior walls by pressing them into capillary active plaster (clay plaster) at about 15 cm from the floor. The clay plaster serves to absorb and transport potential moisture. For that purpose, in a first step the clay plaster was applied to the exterior wall until it formed a level surface. Then, the reed panels were pressed onto the wall and fixed. The panels were fixed to the timbers using long wood screws and insulation discs or they were attached to the partitions with insulation support In each case five fixings per m² were used.
Illustration 2: Fixing the first insulation panel (6 cm).
For testing purposes the clay has been imported together with the reed panels from Turkey. That is why it shows an unusual greyish colour. After making the clay lean the clay plasterer the clay rendering mortar is applied by hand.
3. The insulation panels were placed staggered to avoid cross joints. Special care was taken to avoid hollow spaces between the insulation layer and the exterior wall to reduce the risk of condensation. After a first drying time (app.14 hours) of the panels in the clay mortar the panels were plastered.
Illustration 3: The staggered reed insulation panels and how to fix them with insulation support.
Illustration 4: The wall build-up: On the outside the double-shell masonry with an inlaying layer, on the inside the insulation panels, pressed in clay. The horizontal application of the panels makes plastering easier.
4. In the next step a WEM wall heating is attached to the wires of the reed panels with tie wraps. A horizontal chase, containing inlet and outlet pipe, has been installed below the reed panels. The same has been done with the electric cables. As a last step the chase has been covered with the new oak flooring.
Illustration 5: The wall heating after plastering. The easy installation with the help of tie wraps could be done by unskilled workers. Then, the different elements of the wall heating were connected by a plumber.
Illustration 6: The walls after plastering (here, a Hiss Reet wall). Reed stalks are mixed into the final rendering. The floor is made of stamped clay treated with linseed oil.
Illustration 7: The walls after plastering (same shot as in illustration 4) with a new wood window.
