This is an interior shot of the roof flashing looking upward. It is a DuraVent installation. This is the first time I've seen these ventilation slots at the top of the roof flashing. Normally this would just vent from the attic, but in our case there is no attic. The shot is taken of the closet ceiling. So my question is, how to prevent heat loss from the interior to outdoors? There will be a metal trim ring in the closet, but that seems insufficient. Can fiberglass or mineral wool be placed around the base or is that a complete no-no?