Instandsetzung von einschaligen Dächern mit feuchter Wärmedämmung / Restoration of single-leaf roofs with humid heat insulation

The heat insulation layer in old single-leaf roofs often is humid because of the roof This increased humidity is to be considered in the context of restoration measures of the roof and if the yearly moisture fluctuation has to be estimated. Knowledge based on practical experience over decades confirms that effective drying can be achieved by appropriate restoration. Quantitative prediction of the time-dependence of the drying process, however, is not possible up to now. For this reason, the success of restoration of humid old roof systems remains uncertain. In this contribution, test results and a method to calculate moisture processes will be presented. In order to describe the drying process an approach based on diffusion is supplemented by specific border conditions of roofs. Statistical climatic data and temperature as well as vapour pressure, both depending on the chosen structure, range among these parameters. By means of this calculation method, time-dependent drying can be checked and a successful restoration procedure can be suggested. Most important values entering the planning of a restoration measure will be discussed.