A Numerical Study of Methods to Improve Moisture Safety of Ventilated Wooden Roofs

Abstract

The hygrothermal performance of highly insulated, prefabricated wooden roof structures is likely to deteriorate due to the low heat flux to the ventilation cavity. This article evaluates the possibility to improve the moisture safety of such roofs in a Nordic climate by using different control methods for the ventilation rate of the roof and by using thermal insulation above the roof sheathing. The results support the use of adaptive roof ventilation as it decreases the probability of mould growth in the roof. The use of thermal insulation above roof sheathing decreases the probability of mould growth only slightly in a roof with elevated amount of built-in moisture.