I have a gable roof with a gable vent in front, but there is now a cathedral addition
In south Mississippi, I have a gable roof with a gable vent in front, but there is now a cathedral addition in the rear, so there is no longer a rear gable vent. No ridge vent, no soffitt vents. It is an unconditioned attic with HVAC ductwork. The air handler is in a closet below the ceiling. The fresh air intake is located in the ceiling of the front porch which is a cantilever.
I have two registers going from the original rear gable wall into the new addition which is split into two equal rooms, each 14’x16′.
How do I create a satisfactory envelope?
Do I do a floor, wall, ceiling in the original structure, and leave the HVAC ducts unconditioned, or can I use open cell, or 1″ polyiso sheets on the undersides of the rafters for a roof envelope?
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