Riskbedömning för mikrobiell påväxt i ett välisolerat parallelltak

Sammanfattning: Nine out of ten small houses in Sweden are today constructed with cold ventilated roofs with attics. In a study made in Sweden, 72 % of these have shown high moisture conditions which have led to moisture related damages. To avoid these problems, and also get a larger volume inside, it has become more usual to build parallel roofs. Because of the parallel roofs sealed construction an inspection is not accomplishable. Some studies have been made by computer programs to investigate the risk of moisture damages and mould growth in this kind of roof. The purpose with this study was, with practical measurements, to examine if moisture problems occur in parallel roofs. The practical measurements were processed in the airgap and wood and registered relative humidity and temperature to give information about the condition of the wood and possible mould growth.To compare the results from the practical measurements, simulations were made in Wufi Pro 5.3 and Wufi Bio 3.2. The simulations showed lower relative humidity than the practical measurements, which can be explained by the limits of the programs and also misleading settings. The practical measurements showed very high relative humidity throughout the roof. By this reason the parallel roof cannot be considered risk-free from a moisture point of view.