If you have a tiled wall (white subway) and want to install a perimeter base tile (i.e 1x1 mesh) over the top of that. I’m thinking possibly a liquid nails but want some opinions on this.
An adhesive that spreads evenly. Be careful with anything that will not spread evenly creating a void to eventually crack. Their are non shrink grouts for this application. be slow to buy and cautious to listen to opinions. Good Luck.
It is best to first scarify or rough up the tile surface you wish to tile over. Then you must use a highly modified “stickier” thinset such as Laticrete’s 254 (Mapei also make a specific thinset for this purpose). Good luck with your project.
Tile over tile is typically the “cheap” solution, isn’t highly recommended and should only be considered when there is no other option. That being said, I would consult the tile manufacturer and make absolutely sure the tile is well sealed. Any moisture that might get behind the tile, either through the grout or caulking could cause major issues with tile adhesion and mold/mildew.
Good luck.