Flooring Tile - grouting marble 12 x 12 tiles

We have laid a floor with marble made in China. Unknowingly we left about a 1/4 inch grout line and used the unsanded grout. We have put down a second grouting (after firt application completely dried) but we now have some problems. First, when cleaning off the tiles, some of the grout was removed, leaving as less-than-level grouting. Second, grout was allowed to dry longer than should have, and we have some haze that seems almost impossible to remove. Questions: Can we go in and with sanded grout, finishe the project? and next: What would you recommend to help remove the haze off of this marble? Can we use vinegar and water? Will it be safe and leave the shine on the marble? Thanks. This is my first time visiting this site. I hope you can help me. My husband did the tile work and grout work...it is my job now to finish it!!!thanks.

This is a tall order.

For the haze I would go to a tile store and ask for a professional cleaner that will remove haze from marble tiles. Marble is very fragile -- don't use anything not recommended.

Whether the sanded grout will stick depends on how deep the joints are. I would think you'll have to remvoe some of the unsanded grout, though.

I'd like to be more help, but that's it on the info you've given.

John

thanks...There is still in some places a good amount of room for more grout and there I don't think this would be a problem. But, do you feel that the sanded grout would be the best bet to finish this with, or stick to the polygrout?
Thanks for your speedy answer.

Betiboop?

You could experiment with the unsanded grout (polygrout?), but it will take several applications, if it works at all. The joints you've described are almost unheard of in marble tile installation, so it's really difficult to say.

Generally, joints wider than an eighth of an inch (in tile or stone) are grouted with sanded grout. The fine sand gives the grout substance.

John