I have a sound 80- or 90-year-old, two- story frame house with aluminum siding. When I had hot-water heat put in the house, the attic was insulated with 3-inch- thick, fiber-glass batts with a vapor barrier. I have never had any moisture problem inside the house, but huge icicles form in the winter. The attic isn't ventilated, and whether it's caused from the sun on the roof or heat rising with insufficient insulation on the attic floor, or a combination of the two, I don't know. Should I turn the batts over and/or put another three inches of insulation on the top of the present batts?The temperature goes to 20 degrees below zero F. here in the wintertime. Should I have louvered vents in the attic and leave them open the year round? Helen La Moine Bath, Maine
Indeed, you do have too little insulation inthe attic right now and should add more -- perhaps as much as R-30. That's equivalent to about 9 inches of fiber glass, for example.
As far as the icicles forming on the outside of the house, along the eaves, that's another problem, according to one insulation expert. it's probably the result of snow and ice melting on the roof and running down into the shady spots on the roof. I can't bet any suggestion about how you could eliminate the problem -- unless a reader can inform us.
Yes, you should have vents in the attic -- and they should be kept open all year long so as to eliminate any condensation that might develop up there.
There is a Federal Housing Administration specification on venting an attic. You can write to the FHA in Washington, D.C.
I believe the spec calls for one square foot of free opening, such as a louver, for every 300 square feet of attic space, unless, of course, the attic is mechanically vented.
You need adequate ventilation in the attic, especially in the wintertime.