Hygrothermal behavior of window/wall interfaces

Research on the hygrothermal behavior of window/wall interfaces was conducted in the dual-chamber climate simulator using two types of PU foam adhesive without additional sealing films. These were compared with a conventional joining filler with sealing foam along with an inner and outer film under the same climatic conditions.

For this purpose, two typical plastic windows were installed in line with standard practice in an external single-story monolithic wall. The complete façade, consisting of the exterior wall and the two fully integrated windows, was then erected in the dual-chamber climate simulator. This was studied in the simulator for a period of 28 days under environmental conditions of 0 °C on one side and 23 °C on the other with a relative humidity of 60 percent.

The aim of the research was to evaluate the hygrothermal behavior of the different sealing systems. The scientists measured the increase in relative and absolute moisture levels over the test period as well as the mass-related moisture content of the foam samples.

Their evaluation revealed a similar or slightly higher moisture increase in all joins using PU foam adhesives compared to “standard” joins using films.