Window moisture and attic mildew
Q. Moisture condenses on the inside of our wood-sash windows despite the fact that we have triple-track aluminum storm windows outside. What can we do to prevent the condensation which is ruining the paint and wood around the windows?
* Mildew forms on the inside of the north-facing portions of our roof. The house is wood frame with an asbestos shingle siding. The attic floor is insulated. the roof rafters and the gable ends where the two vents are located, however, are not insulated. Can I treat the mildew with a bleach, and if so, will it harm the wood? Would insulation added to the attic roof help? What long-term solution do you offer? Robert R. Orr Paramus, N.J.
A. To reduce the condensation on the inside windows, buy a kit, such as that made by Plaskolite Inc., PO Box 1497, Columbus, OH 43216, or its equal. Install the sheets over the windows, following the manufacturer's directions.
Of course, whatever you do to reduce the humidity inside the house will lessen the condensation.The reason for the moisture is the damp inside air hitting the colder window glass. Presto! Condensation.
* The mildew in the attic is again caused by excessive humidity in the home. In other words, the attic needs more ventilation. Increase the number of louvers in the gable ends so as to compel more cross ventilation in the space. Gravity roof vents also help.
It is unlikely that adding insulation to the roof or gable ends will stop the "sweating."
If the addition of louvers and vents fails to produce the needed ventilation, then you may have to install an attic exhaust fan that mechanically ventilates the area. You have to get rid of the moist air in the attic if you want to stop the mildew.
The application of a bleach solution may indeed thwart the mildew, but only temporarily. Mildew is very tenacious. Until the humidity level is reduced the mildew will probably continue, making more than one application of the bleach solution necessary.
Moderate amounts of bleach should not harm the wood framing.