Hygro-thermal response of a ventilated attic to the future climate load in Sweden

Universal in most climate change scenarios for the 21st century is the increase of the global mean temperature. By the end of the century the increase may be 1-6 oC depending on the chosen emission scenario. Climate scenarios for Sweden point to a warmer and more humid climate in future. It can be expected that the building parts, which are already susceptible for moisture load, will degrade more in future. In Sweden, a ventilated cold attic is a typical representative of a moisture-sensitive construction part. This paper investigates numerically the hygro-thermal response of a typical ventilated attic to a possible future climate load in Sweden. The hygro-thermal conditions in the attic are assessed by a mould growth index (MGI). The results showed the increment of MGI in future for all test cases. The analysis showed that the orientation of a roof and the moisture load to the attic from a dwelling underneath are the influencing parameters on MGI. Since the latter is governed mainly by the ventilation system in a house, the type of the ventilation system is important design parameter for the prevention of future moisture problems in ventilated attics