Thermal Rehabilitation of Existing Building Enclosures by Using VIP (Vacuum Insulation Panel) Sandwich and Timber Based Panels

Today, in Austria, the major part of energy-saving potential and therefore possible reduction of greenhouse gas emissions can be found in the thermal renovation of the existing building stock. In the majority of Austrian cities, quite a large number of historic buildings with ornamented or even landmarked façades exist and preservation and protection of the original substance is obligatory because of strict monument protection regulations. Beside that, existing buildings are often built along the road building line and sometimes an encroachment with external insulation is prohibited due to building regulations. So, in these cases, inside insulation systems are mostly the only way to decrease the heating energy demands and even to improve the indoor comfort conditions of these buildings.

This paper will present the hygrothermal performance of external masonry walls with inside insulation systems made of newly developed VIP sandwich panels and typical insulation systems consisting of woodwool panels in the climate of Austria. The study focuses on the assessment of moisture accumulation inside the construction and therefore the potential risks of mold growth up to freeze-thaw damage. Sandwich wall panels made of a vacuum insulation core covered with woodwool boards were developed and their interaction with the hygrothermal conditions of existing brick masonry enclosures was analyzed and optimized by using hygrothermal models (heat & moisture simulations).

Additionally, a test setup with the new insulation system was installed at an existing building to evaluate the feasibility and to analyze the enclosure’s performance under real conditions. First in-situ measurement results, taken at this experimental setup, will be discussed in brief.