Hygrothermal analysis of technical solutions for insulating the opaque building envelope

The application of insulating materials for energy refurbishment of buildings improves the thermal transmittance of the envelope. However, if not properly planned and realized, it could reduce the wall's drying potential, modifying its original features and leaving it generally more humid. This can lead to moisture damages, humid insulation material and risk of mould growth. To avoid any problem related to the increased presence of water in the building envelope, it becomes therefore essential to perform the so-called hygrothermal assessments. In this regard, the international standards offer, beside the traditional Glaser method based on the mere vapour transport, the use of dynamic hygrothermal simulations. These allow to simultaneously consider the transport and storage of heat and moisture in building materials, the influence of climate (including rain and solar radiation in different locations), user behaviour and initial conditions. The aim of this paper is to compare Glaser and dynamic methods and to highlight their advantages and disadvantages, considering the different approaches to the evaluation not only of superficial and interstitial condensation, but also of durability, considering biological attack, freeze/thaw cycles, corrosion, etc.