Several years ago I tiled bathroom floor and I recall one of the steps was to keep the grout moist for several days by using a spray bottle and lightly misting the joints. I'm no pro so someone must have told me it was a necessary step.
Well, I'm doing some more tiling and I don't see this as a step in any of the online guides I have read, no one in Lowes knew what I was talking about and even talking to my sister who has the pros do her tiling said they don't do this step.
So, what is the answer? Do I need to mist the grout or not?