Messtechnische Analyse flachgeneigter hölzerner Dachkonstruktionen mit Sparrenvolldämmung [Teil 1]

Measuring investigations of the hygrothermal behaviour of timber flat roofs — Part 1: Non-ventilated compact roofs with waterproofing membranes.

For compact roofs with roof waterproofing membranes very high inner diffusion resistances are counterproductive. This kind of construction has virtually no drying potential. By the use of smart vapour retarders a higher diffusion based drying rate can be achieved. Five industrial manufactured, full scale low pitched and leakage free timber flat roofs with roof waterproofing membranes, different smart vapour retarders and inner sheetings were investigated under sun-exposed and fulltime shaded conditions. During the 17 months long investigation period the hygrothermal behaviour of the roofs differs mainly due to the different solar irradiation. In the exposed roofs the climates at the inner side of the cavity were clearly more critical as at the outer side of the cavity. All shaded roofs showed a very critical hygrothermal performance. Despite high moisture loads in the buildings and in the cavities no mould could be found in the inspected roofs.