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How to insulate chimney-roof clearance?
I am looking for ideas on how to insulate, and control condensation in the space between my Chimney and foam core roof panel.
I currently have a 2Ă˘â‚¬Âťclearance between my foam core roof panel and my stone fireplace. The roof sheathing is Ă‚ÂľĂ˘â‚¬Âť clear of the chimney. The chimney opening is in the center of the house, and exits the roof about 3Ă˘â‚¬â„˘ below the ridge. The house is an oak timber frame with structural insulated panels on both the walls and roof. It is tight. Also, I operate a woodstove in the fireplace throughout the winter. Finally, I run Panasonic through-wall exhaust fans in the winter season to remove humidity and achieve a healthy level of air change. I live in Northern New Jersey.
Over the past two years I have gently placed (not stuffed) fiberglass insulation in the void between the chimney and foam core panel. I have not trimmed out the 2Ă˘â‚¬Âť opening, thus the insulation is exposed to the room inside. The result is that humidity seems to migrate up through the insulation, condense and freeze at the top near the copper flashingĂ˘â‚¬Â¦then on a warm day, when the sun strikes the chimney/flashingĂ˘â‚¬Â¦. the condensate drips back down through the insulation into the house.