I have an old fireplace and hearth that I want to get rid of. It's original to the house, in a bad location, and takes up too much space in the room. I'll never, ever use it. There is a second fireplace in the family room that gets regular use.
The catch is my oil-fired boiler is venting into the chimney from a utility room so I can't just seal off the top and be done with it. I will drywall over the opening so I need to make sure no moisture will accumulate inside the wall.
I'm thinking I need some sort of insulation stuffed in the opening (below the boiler vent) and then a vapor barrier/moisture seal as well. Or should this be reversed? Vapor barrier then insulation below that?
Does this sound reasonable? What materials should I use for insulation and vapor barrier?