fixing old tiles that are coming loose
The century-old tiles in my fireplace surround (an original, now unused gas fireplace) are coming loose in places. Some are still adhered well, but in a few patches, groups of 3 or 4 tiles are pulled away from the wall and only the grout and gravity is holding them vertical.
I haven't any idea how to go about repairing this, but am hoping it won't involve removing all the tiles and putting them back.
Suggestions? Resources? All help and advice welcome!