Last night, temperatures dropped to a chilling -10°C, and I noticed some moisture near a switch on the wall in my walkout basement, close to the door. The insulation looks mostly dry, but there are some marks suggesting it may have been wet at some point. The rest of my house stayed warm, not dropping below 69°F, but I haven't checked the basement at night before. Could the extreme cold near the door cause freezing moisture? Why is there any moisture there at all?
3 Answers
What’s behind the wall where the switch is? Is it exterior or interior?
It's pretty common to see moisture in areas where there's a big temperature difference. In your basement, that might be condensation where warm air from inside meets the cold air from outside. Make sure to check behind the insulation to ensure there's no hidden condensation. If there's an electrical box there, maybe try using some spray foam around it to help with insulation.
Honestly, I wouldn’t stress too much. Since you mentioned it's near a large pane of glass, and with the cold outside, it’s likely just condensation forming. That cold air can easily seep in and meet the warm indoor air, leading to moisture on surfaces.