I know it is not typically done, but we are fixing up a 40 year old rental condo that has one inch tiles (original) in both small bathrooms. There is no damage or cracking anywhere in the tile and it seems that it forms an extra water protection or barrier between us and the floors below, We see no reason that we cannot lay new tile on top of it when we update the bathroom, if we do it properly. We would like some advice on the best way to do this and also how to handle the slight increase in height for the toilet re installation. Thank you carolitis