I have an approx. 18" x 3/4" crack in my bond beam right between the two rows of tile at the water line. There seems to be only one company who does this kind of repair work in my area (Phila., PA) and they are very busy after this past Winter. Is it OK to break up the loose mortar and smooth fresh plaster over the crack (not replace tiles) for the time being for aesthetics? Are the tiles at the waterline only to prevent a visible line in what would be white plaster? The company is months out for scheduling and their price definitely reflects their backlog.