live in 60 year old house. chimney brick from top to about 6-8 down are shearing off leaving about 2/3 of brick in place, with some of the mortar falling out, some remaining. 1) any adhesives to put over top of what brick remains intact to prevent further deterioration? 2) anyway to chisel out brick at a time and replace the 20-30 bricks that are effected and slip new ones in (safely? and practically?)? 3) Contact persons for matching fire brick in St. Louis area availability?