Internal Insulation-Compound Elements made of renewable resources

19th century heritage buildings in Vienna have a high heat energy requirement of 120-160 kWh/(m²·a) due to low thermal quality of the exterior walls. An application of external insulation for thermal improvement is often impossible due to monument preservation which prohibits major changes of the facades. WHISCERS™ (Whole House In-Situ Carbon and Energy Reduction Solution) is an efficient method for thermal retrofitting of historic buildings by applying internal insulation. It involves measuring the walls of the building using a laser device that enables fast and highly accurate measurement. The digital data is then sent to a factory-based off-site cutting machine that cuts the composite-masterboards with great accuracy without any mess at the site. The elements are then delivered to site and are fitted to the walls.


As part of a multinational consortium, the Austrian part adapts the WHISCERSTM system to the local conditions of Vienna. It mainly deals with the replacement of the rigid foam boards used in the original system in Great Britain by renewable raw materials such as wood and wood-based materials, further optimization of the retrofitting process and improvement of the hygrothermal performance by using appropriate materials and constructions - to develop a more sustainable system. Four variants are examined, where one is treated as an example in the present article. The presented variant illustrates a new system solution based on wood fibre boards of different densities to enable the best possible adaptation of the system to the imperfections of the existing walls. 


Hygrothermal simulations are carried out to evaluate the suitability of the four developed variants, before they are hygrothermally monitored in two Viennese buildings during the heating period. The results of the simulations indicate that no risk of condensation occurs when applied in existing, typical brickwork buildings having appropriate climatic conditions. The evaluation of the measured data confirms the results of the simulation, and illustrates the advantages of the dry internal insulation system based on wood fibre.


For further Information please see TISS and/or contact Research Coordinator Associate Professor Dr. Alireza Fadai.