OEKO-ID - Interior insulations to improve thermal efficiency of buildings - feasibilities and limits of ecological and open-diffusion insulation systems

In the course of global efforts to save energy and the introduction of the energy performance certificate for existing buildings in Austria as of 2009, improving the thermal efficiency of existing buildings plays an important role. In the past, renovation of inner-city, in some cases listed buildings by means of exterior insulation involved a great deal of time and work, if indeed it was possible at all as a result of site limits, richly structured faades or difficult ownership situations. Technically, interior insulations offer a rational way of reducing the U-value of existing walls by around 50-70 % and increasing interior surface temperatures that play a essential role in terms of comfort. In addition to well known versions with an interior vapour barrier or vapour-tight insulation materials, more recent open-diffusion constructions are intended to avoid harmful water vapour condensation by taking advantage of the good sorptive and capillary conductivity of the insulation material. Aside from their suitability in terms of practical construction, the ecological compatibility of the building materials will also play a special role in future. In addition to a fundamental analysis and further development of building section joints such as transitions to wooden beam ceilings, partitions, window and door reveals, that tend to pose certain problems in terms of interior insulation, the aim of the project is to draw up a product-neutral assessment of the use of ecologically safe building materials for interior insulation. The humidity loads, that may in some cases be critical for organic building materials, are determined by means of on-site hygrothermic measurements on an adapted existing building over two condensation and drying periods. The mould risk is assessed by developing an innovative molecular-biological monitoring method, that will be capable of detecting any microbial attack in an almost completely non-destructive manner. It is also planned to investigate the possibilities and limits of using hygrothermic simulation calculations in order to estimate the effects of future interior insulation measures without the need for extensive measurements and to promote the wider use of this sophisticated energy-saving measure. The outcome of the project will be a catalogue of potential problems, particularly in terms of humidity, and solutions, as well as a concept for active transfer of knowledge to decision-makers and builders.