The sealer will make the grout look darker whilst wet but should dry back to its normal colour as its translucent, I always seal an off cut first to make sure there isn't any problems with the
tile. These large format porcaline tiles don't come cheap so any major errors can cost you a fortune.
In regards to Akhter's post the biggest problem with vitrified tiles is lippage, if the floor isn't totally flat your lining yourself up for all kinds of problems. This is because the tiles are squared off leaving a sharp, noticable edge to the
tile if badly laid (those 1-2mm steps that you might get away with ceramic tiles now feel huge).
Always find any high point in the room to work from and take your time. I normally set the floor out and take a good 15-20 minutes to lay the first few tiles, making sure they are perfectly level. You can then build up your speed by working off those tiles. If one
tile corner is a little low or high you end up trying to compensate with the other tiles to reduce that sharp corner. This tends to throw everything else out of hight.
One tip is to lay the
tile and close the grout joint up completely, the tiles should be running as one smooth surface. if the
tile is low then lift the
tile and add more adhesive, if its too low you may be able to bed it in a little more or you may have to lift the
tile and use a smaller trowel to remove some. Once you have got it right gentley pull the
tile away and stand your spacers in.
cjbombero