I tore out the drywall around our wood fireplace to redo the basement. I noticed there is a strong cold draft coming through the insulation that is tucked between the bricks and the studs. The fiberglass is also black in spots where it's been "filtering" air infiltration.
If I pull the insulation back I see about a < 6 inch air gap to the brick that surrounds the chimney pipe (I assume).
I know the first problem is sealing from the outside must not be adequate if that much air is coming through, but the second question is how do I insulate this properly from the inside?
Some of the gaps are very large. Fiberglass insulation does not seem like the appropriate material here. Above that the MIRA-BILT aluminum insulation board is the only thing between the air gap and the drywall.