So, you’ve just had your new tile installed and a day or two later you find a dull haze or light streaks on the tile. What you are seeing is grout haze that has been left on the tile from the installation.
When installing tile the final step is to apply grout to fill in the spaces between the tiles. To simplify things, think of grout as fine colored sand with a bit of cement or another adhesive mixed in. As the grout is shaped with a damp sponge the sand is pushed between the tile and some ends up on the surface. As the grout hardens the installer will wipe the surface of the tile removing the grout. It will take several rounds of wiping to clean the tile surface and the sponge and rinse water need to be cleaned between rounds.
For the last few rounds, the sandy part of the grout will be stiff and will stay off the surface of the tile. The water on the surface of the tile may still have some of the adhesive material in it. At this stage, the tile is wet and looks clean. When the tile dries, however, the adhesive in the water can appear on the surface of the tile as haze. It takes patience to wait for the tile to dry and sponge again or buff with a clean very slightly damp towel to remove the haze. It can be at the end of a long day or late at night and the thought of wiping it one more time is just not in the cards. The tile is wet, but it looks clean, so you quit. The next morning arrives and there is haze on the tile.
If you have haze, first read the grout manufactures label or website for instructions, you may need to wait a day before trying to remove the haze or you may need to move more quickly before the haze hardens more.
The first thing to try is a damp clean cloth. If the grout is still a day or two old this may be all you need to do. Using firm flat pressure wipe the tile and be careful not to dig any grout out. Check the towel for a colored film to see if you are getting any haze off.
The second method is to use a mild acid solution of 4 parts water to 1-part vinegar. Apply the solution, let stand a few minutes and wipe off with a towel or clean sponge. It is important to rinse off the tile with clean water afterward.
If those two methods don’t do the job, then a commercially made grout haze remover is the next option. There are many brands available. Take care to find the one that is best for your material. Certain stone tile are very acid sensitive and extra care must be taken. Follow the manufactures directions carefully and make sure to rinse the tile well afterward to fully neutralize any acid-based cleaner.
If those options don’t work, call in a professional. Explain the situation and the steps you have taken.