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Improving durability of wooden beam bearings after a thermal renovation via interior insulation is highly demanding for planners. Because of an isolated thermal bridge in the area of the wooden beam head the risk of condensation water forming in this area increases after installing interior insulation. The problem with wooden beam ends has been analysed increasingly in the last few years by many research institutions as wooden ceiling constructions are common in existing buildings. Furthermore, thermal renovation makes a vital contribution regarding improving the energy-efficiency of existing buildings. In this paper a method to temper wooden beam ends is introduced. It is a patent pending which is currently developed further using laboratory-prototypes in a double climate chamber. This technology is based on thermo conductive types of sheet metal, which are driven into the construction at the joint between the wooden beam and the surrounding masonry. The thermal energy is provided by a heating pipe and fed into the metal. Because of the metal's high thermal conductivity, heat can be fed specifically into the beam's end in order to avoid wood rotting at this crucial point. Calculating the beam's end temperature control was done using three-dimensional HAM simulations with air flows in the ceiling cavity being taken into account. The results of different measurements in the double climate chamber as well as the HAM simulations clearly show that the durability of an interior insulation can be increased via a temporary and local tempering of wooden beam bearings. At the same time the risk of wood rotting at the ceiling's bearing structure is minimised. Comparative analyses show that this method of tempering the beam ends is especially energysaving as the energy input is low due to the special feeding of heat via thermo conductive types of sheet metal.

pillaraktiven Innendämmsystemen, aber auch Flachdächer in Holzbauweise, bei denen aufgrund der fehlenden Berücksichtigung der solaren Einstrahlung auf die Dachoberfläche oft Versagen prognostiziert wird, obwohl die Konstruktion in der Praxis funktionstüchtig ist. In diesen Fällen muss dann auf eine (

Improving the energy efficiency of typical 19th century townhouses in middle Europe the focus on the wooden beam bearing's hygrothermal performance has become more and more important during the last years. There are several issues for the risk of rotting of the wooden parts of the ceiling, because the retrofitting process of the masonry totally changes the hygrothermal conditions inside the wall. Applying an interior insulation or changing the airtightness of the building envelope as well as the introduced moisture from the retrofitting process lead to a moisture increase inside the masonry and might cause rotting of the ceilings' wooden beam ends. This paper introduces two demonstration objects which were retrofitted during the last years. Temperature and humidity sensors have been integrated at the wooden beams' ends to show the hygrothermal conditions during and after the retrofitting process. In the first building measurements started at the beginning of the renovation in September 2013 and are still being carried out. To compare different situations the monitored beam bearings are situated in two different retrofitted wall constructions, an inside insulated and a not insulated wall. Additionally, different indoor climates in the flats above and below the measured ceiling are monitored. In the second building 16 wooden beam heads situated in two different storeys with differing masonry thicknesses were measured. In this demonstration object the influence of building construction moisture from the renovation process as well as the drying out process were evaluated. In conclusion, the wooden beam heads' durability will be assessed based on the measurement results and possible risk of damage influenced by the retrofitting process.