I've looked all over and can't seem to get a definitive answer, so I'll pose the question to all of you handy HTF folks. I recently repaired part of the grout on my bathroom's tile floor. I've decided to re-grout the rest of the floor so it all matches. The problem is, I only have one bathroom, so I will have to walk on it. How long before it is safe to walk on the grout? Thanks!