Un sanded Grout on Tile wall - Hairline cracks and Air holes.

I recently redid my bathroom, with 12 inch tiles, with about a 1/4 inch space between them. I finished grouting them with unsanded grout(when I discovered I should have used sanded grout for 1/4 inch space). Anyway, I went over them before sealing, and found air holes and hairline cracks. What should I do - go over it once again with grout and then seal? or dig out the grout and start again with sanded grout?

I just did a bathroom shower the exact same way and had the same results: hairline cracks two days after I had grouted.

Did anyone give you a reason why?

Hickey

the sand keeps the grout from contracting so much with the extreme varying temperatures in a bathroom. You can buy the pre mixed mildew resistant grout from Home Depot and do a skim coat over the existing grout..........that should take care of ot.