My home is 14 years old. I have been using a 40 pint dehumidifier at 50% until this spring. It was only after discovering mild amount of mold under my fiberglass insulation that I felt I needed to improve upon what I had.
My basement is almost 3000 sq. ft. I had purchased 2 70pt. dehumidifiers, placing them on opposite areas of the basement. (as I found the humidity was different in one area than the other).
The humidity now is between 40 - 45% where it was at 67% with first utilizing the new humidifiers.
I have noticed cracks that were not present in my walls and floors before, beginning at a 55% humidity level in the basement. I have a neighbor who uses 2 70 pt. units in a smaller basement at a lower humidity level with no complaints, so I was surprised by this change.
It has been 4 months later and the cracks have stabilized.
Any thoughts on why this would occur?