I put a wood burner in my finished basement and the pipe needs to through a wall(which no longer had drywall and is now cement board and stone) then travels 36" to the chimney. The space behind the wall is dead space due to the way it was laid out when the basement was finished. The nearest stud to the pipe in the dead space between the wall and chimney is about 8". Would it be acceptable if I just lined the inside of this dead space area with cement board to make it non combustible and wrap the single wall pipe in kaowool?