Below you can find typical weatherproofing problems with windows and how to correct them:
- There is moisture on the inner surface of the glass: the apartment ventilation is insufficient, and the space is over-sealed (like a bottle). This means replacement air cannot get in, and extract ventilation doesn't work. Remove a few cm of the seal from the top of the inner frame and the lower outer edge of the frame.
- There is moisture between the inner and middle frames: the seal leaks, it hasn't been installed, or the window glass is no longer weatherproof. This can be caused by old glazing sealant or the window glass becoming loose. To correct this problem, re-seal the window with, e.g., silicone.
- The outer glass is moist or frozen: the outer frame is over-sealed. Remove some seals by experimenting with 3 cm strips from the top and bottom so that the air can circulate and the moisture is removed. Too big a gap will cause the inner glass to freeze, so you will find out by experimenting.