Fibrous insulating materials are used both for building and industrial applications. They present interesting characteristics of performance for low and high temperatures and also for moisture and wetness. In the case of industrial applications the performance of insulating materials under high temperatures is of particular interest whilst in the case of buildings the possibility of changes in the building materials' properties because of the penetration and residence of moisture in them is always to be considered. In the case of insulating materials such damages initially may have an energy cost, since they reduce the insulating ability of the material. Furthermore, there may be economic consequences, like in the case of the insulating material and/or the coating becoming Wet, with the implied partial or even total destruction of the latter, whilst in extreme circumstances there may occur consequences for the safety in case of corroding the subjacent concrete. Nevertheless, even in the simplest case of wet materials, the consequences are not to be regarded as insignificant. A model was developed which. allows the evaluation of stone wool under varying temperature and humidity conditions. The latter characteristics were also verified by long-term laboratory experiments. The methodological approach, the experimental procedure and the results are discussed in this paper. (C) 2008 Elsevier B.V. All rights reserved.