Q.During the winter mildew develops on the lower part of the exterior wall of a closet. Moisture-absorbing material hung in the closet is ineffective, and leaving the closet door open is not a satisfactory solution. My guess is that the house walls are not insulated and thus cause the condensation problem. Could we drill large holes in the closet walls and put in some form of insulation between the studs? Janet Bredlau Westfield, N.J.
A. In my opinion wall insulation might not stop the mildew problem since the absence of insulation may not be the culprit. Pellet-type or blown-in insulation in exterior stud walls is possible, but for most do-it-yourselfers it is an unlikely task.
Invite a reputable insulation contractor to inspect the premises and suggest a method and price for wall insulation, if desired.
Now about the mildew and its cause and cure. Humidity, or less-likely clandestine moisture, triggers the mildew in the apparently unventilated closet.
Since mildew is absent during the summer, the possibility of a leaky pipe in the wall or leaks through the exterior siding is remote. Nevertheless, satisfy yourself that neither a leaky pipe nor a leaky wall is a moisture source.
To remove the mildew, scrub the infected wall with a mixture of 4 to 8 ounces of household bleach in a gallon of warm water. Let it dry. Then repaint the wall , using a top-quality paint mixed with a mildewcide formulated by your local paint dealer.
Leave the moisture-absorbing material in the closet. Also leave a low-wattage bulb burning in the closet day and night.
You might install a pair of louvers in the closet door, one high and one low, to provide ventilation.