Roof replacement in unique house
Roof deck/structure is 2.75″ thick T&G decking
Interior is all cathedral ceilings
Interior finished ceiling is the T&G decking
All insulation has to be on the exterior side
There are limits to how much the roof can be built up due to windows, etc
Right now the house has minimal, if any, insulation in the roof
The plan is to strip the roof back to the T&G decking and start fresh with 2″ of Genflex PolyISO insulation board, then furring strips on that, then 1/2″ OSB sheathing. The hope is adding some venting helps with condensation and ice dams.
The question is, should there be some sort of vapor barrier? If so, where? I don’t think there is anything now.
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