Advancements in Hygrothermal Monitoring: A Comparative Study of Sensor Reliability and Installation Strategies in Construction Elements

The prevention of moisture related damages in construction is extremely important to ensure the durability of buildings, to save resources in their management and to ensure safe and healthy environments for occupants. The assessment of the internal hygrothermal conditions of construction elements using real time monitoring is a powerful strategy to prevent them and can yield profound insights into the dynamics of each individual case examined. However, it is crucial to identify reliable sensors and installation strategies. The use of capacitive and resistive sensors is a prevalent approach; however, it is not without challenges. Drilling into the stratigraphy to place these sensors requires boreholes, which not only potentially alter the measurements but may also be impractical, both in existing buildings and new constructions. The ideal scenario is to integrate sensors during the construction or retrofitting phase to obtain reliable data but also in this case a careful planning and a correct selection of the sensors is needed. This study investigates these challenges in a controlled environment using a double climatic chamber and a real-scale timber frame façade that integrates a moisture-adaptive membrane on one side and a bituminous membrane on the other side to reproduce the stratigraphy of a flat roof. Different type of sensors as well as different installation approaches (including before and after assembly) are used and assessed. This research presents a new method for installing sensors after assembly. When applied precisely, the approach generates accurate sensor data comparable to pre-installed sensors. However, rapid changes in humidity can cause a decline in accuracy, and it’s important to restore the structure’s airtightness when mounting sensors in existing structures to ensure reliable data collection.