I live in Maryland in a small colonial built in the 80's. The family room has a vaulted ceiling and fireplace with a wood burning stove insert. The fireplace chimney is red brick and runs up the center of the wall. One side of the chimney is inside the house, the opposite side faces the outside.
During the winter, a lot of cold air is getting into the house where the wall meets the chimney. There is a gap of about 1/8" between the brick and the wall. The space is even larger at the mortar gaps.
I was thinking of getting a hand-held can of that spray-foam insulation with the straw nozzle and and going up height of the wall/chimney to fill in the gaps.