So we carefully removed the old tile and the loose areas of the original mud bed.
In the removal process we had a very nice surprise, they had tiled underneath the fireplace woodworking so all of a sudden we have replacement tiles that are a perfect match! They were completely concealed so we don’t need to put them back underneath but will use them to fill in several missing areas.
In addition to the find, we also have matching blue border tiles that we salvaged during the 2nd floor bathroom renovation. These are very unique, 100 year old tiles and would be almost impossible to match, so we are lucky!
We aligned the top of the tile with the top of floor (It had previously settled) and it all came together well. The orginal tile had minuscule joints which we matched so there is not a whole lot to grout.