ASK THE EXPERTS QUESTION We had an issue recently with a White Thassos mosaic where the individual pieces on the sheet had inconsistencies in spacing on the mesh, with a few pieces exceeding a 2mm joint. The factory specifica- tion was made to a 1.5mm joint, but I’m told from our vendor that various factors (handling, shipping, etc) can cause shifting to occur over time. Can you confirm if there’s an indus- try standard tolerance for deviation on these types of mosaics? I’m sure the Marble Institute of America has something to this effect, but I don’t have access to their documentation to verify. ANSWER I am able to provide the specifica- tion for ceramic mosaic tile from ANSI A137.1. Table 6 of ANSI A137.1 states the specifications for mosaic ceram- ic tile, including mounting/crooked tiles and for mounting/wide & narrow joints. Those specifications are: • Mounting/CrookedTiles:Individual joint range