I have laid some new tiles in my hallway and they are a larger tile with what looks like a grout recess to make them look like 4 smaller tiles. My question is, are those lines meant to be grouted or should they me left ungrouted and just grout the main grout lines between the large tiles. The ‘built in’ grout lines are roughly 2mm wide but only 2mm deep. Is that enough to hold the grout in over time?
Many thanks in advance