Large Format Tile Shower Floor . Play around with ideas for tile layouts, including staggering in a classic jumbo subway tile pattern, in vertical rows to make the ceiling seem. I have 3 inch tile now and hate it and the grout lines. Large Format Shower Tile Houzz from www.houzz.com This is due to the high quality materials and manufacturing processes used to make realgres large format porcelain tiles. More importantly, smaller tiles are difficult to clean: It is generally recommended that shower floor tiles are no larger an 6 inches square, in a bid to allow for a greater amount of grout, which in turn, offers a good deal of grip and stability.