How humid it could get inside a cabin
In the summer of 2001, my wife and I found our perfect cabin. It was modern, winterized and even built to high energy-efficiency standards.
To our surprise, our wonderful cabin became a very humid cabin as the mercury dropped in late autumn. A musty odor would greet us when we first opened the door after a week’s absence. Bed sheets felt as if they had been pulled from a clothes dryer with the job half done. Our cabin resembled a large terrarium: heavy condensation on the windows and door, occasionally producing long rivulets of water. The inside window frames of the cabin began to turn a moldy green. Yuck!
At first, we thought the cabin was just too tight. Being fully winterized, we thought, it had to be trapping moist air inside and was not providing a means of escape. Eliminating the three main sources of humidity- breathing, cooking and showering- was not an option. Running a dehumidifier was only a temporary fix. Something else had to be done.
Searching the internet, I learned that excessive humidity in a home can be caused by moisture emanating from the dirt floor in a crawl space and then permeating into the living area of the cabin. Bingo! That turned out to be our problem.
The next weekend, armed with a 100 foot roll of 6-mil poly plastic, I covered the entire floor of the crawl space, overlapping the sheets of plastic and taping the seams with duct tape. The plastic acted as an effective vapor barrier to keep the moisture in the ground and out of the cabin. The result: We now own a dry cabin year round. No odor and no more green window frames.