how to evaluate condensation risk on a surface?

Amandine Piot · Post by **Amandine Piot** » Mon Jun 03, 2019 3:05 am -1100

Hello dear Wufi Team,

I'm currently modelling a house and try to evaluate the risk of condensation on a surface (uninsulated wall).
I wonder how to evaluate this risk, and I see 2 options:
1) I calculate the dew point temperature of the inner air (based on the calculated T and RH); and I compare This dew point temperature to the surface temperature of my wall (inner side). If Tsurf<Tdp, then there is condensation. At least, there would be condensation on a glass plate or mirror. In my case this happens during a few days in winter.
2) I look at the relative humidity in the first node of my wall. In my case the value never exceeds 80%rH.

What should I conclude? Is there condensation or not? I can understand that the "condensed" water is actually absorbed by the (hygroscopic) material of my wall, preventing condensation to accumulate and "roll down" the wall.

What would you recommand in such cases?

edit: I changed the name of the topic as maybe it was not so clear...