Sprayed-on and Plaster-covered Cellulose-insulation without vapour barrier

Investigations on the fundamental suitability of sprayed-on and plaster-covered cellulose insulation for thermal insulation of buildings.

Content Description




Basic situation

In the course of global efforts aimed at thermal renovation of existing buildings, there have been a increasing number of investigations on the use of interior insulation measures since the mid-nineteen-eighties.

Special attention in this context is given to the expected formation of moisture in the wall cross-section according to the Glaser method. Attempts were made to tackle this situation by means of a wide range of vapour barriers, but it soon became clear that branch lines as well as building sections and deformations (e.g. wooden joist ceiling beam ends) pose a problem that is difficult to solve.

It is also known that the Glaser method provides an inadequate description of hygrothermic processes in the wall as it does not allow for capillary moisture transport in the various building materials.


Based upon international research findings and the precursor HdZ project "Investigation of physical and material properties of outside sprayed-on cellulose insulation covered with plastering", the aim of this project is to further develop recycled paper cellulose flakes to create a sprayable, self-supporting, 3 - 8 cm thick body of insulation to be covered with an interior spray-on plaster that is open for diffusion. The aim is to avoid harmful water vapour condensation by taking advantage of the high sorption capacity and capillary moisture transport of the cellulose fibres.


  • Further development of existing transport technology
  • Reduction of drying times by means of new spraying technology and special binders
  • Development of special plaster system open for diffusion
  • On-site measurement of hygrothermic behaviour for a one to two-year period
  • Parallel numeric simulation calculations for identifying parameters for future applications

Expected results

Internationally, a sprayed-on, plastered interior insulation system without vapour barrier based on recycled paper cellulose is a complete innovation. As a result of the special sorption properties of the material, the aim is for the above-described process to cater for the demand for ecologically harmless structures open to diffusion, and to provide a failure-tolerant, inexpensive alternative to existing insulation systems, particular with regard to the renovation of existing (historically valuable) buildings.

Project Partners

Project manager:
  • Peter Kautsch
    Graz University of Technology
  • Wolfgang Lackner
    CPH - Zellulosedämmstoffproduktion Beteiligungs GmbH & Co KG
  • P. Häupl
    Dresden University of Technology
  • Wolfgang Streicher
    Graz University of Technology
  • Robert Schmied
    Wietersdorfer u. Peggauer Zementwerke GmbH
  • Markus Gleixner
    Gleixner Dämm- und Messtechnik


Ao.Univ.-Prof. DDr. Peter Kautsch
Technische Universität Graz
Institut für Hochbau für Architekten
Rechbauerstraße 12, 8010 Graz
Tel: +43-316-873-6245
Fax: +43-316-873-6082
E-mail: kautsch@tugraz.at

Dipl.-Ing. Herwig Hengsberger
Technische Universität Graz
Institut für Hochbau für Architekten
Rechbauerstraße 12, 8010 Graz
Tel: +43-316-873-6807
Fax: +43-316-873-4999
E-mail: hengsberger@tugraz.at