Hello, I have a situation where I’m putting a wall back in where one was previously prior to me tearing half of it out to open between my living room and bedroom to make the bedroom a dining room. I will be framing the wall back up to utilize the dining room as a bedroom once again. With all of this I’m installing a gas fireplace in this wall in the center and will be surrounding it with cement board and then 1/2 inch brick veneer. The rest of the wall will be shiplap attached directly to the studs. I’m wondering if I should install some sort of air barrier behind the shiplap to mitigate the amount of air going through the gaps of shiplap and ultimately making its way up into the attic in the form of heat loss. I live in the northeast ie: cold and should mention the fireplace will not be a heat source but just for occasional ambiance. Other factors behind this wall is the original house chimney for gas appliances that only has some insulation packed around where it penetrates into the attic plus gaps around the top plates of the walls etc.

I live in the northeast and have a Cape Cod style home with a walk in attic that you need to access through one of my bedrooms. This room is always either really hot in the summer or cold in the winter. The attic itself is not insulated except for the wall that is against the bedroom and the floor. There also isn't any sheathing to cover that insulation on the wall so I have lots of air just freely flowing from near the molding in the room. I wanted to seal around all the wall joints and then install rigid foam insulation sheet to cover the fiberglass batts to give it a better R value. Will I have a moisture issue if I put up rigid foamboard insulation on the attic side? Should I just put up some wood sheathing? If no issue with foamboard what type should i use? Thanks