This stress will be tensile during temperature decrease, or compressive. during temperature increase. If the compressive stress level exceeds the column buckling resistance of. the restrained length, then lateral buckling (or snaking) will occur.
Dry Time. In most cases, you should allow the grout to dry overnight before using that room as total dry time may take up to 24 hours. If you are thinking about sealing your grout after you have installed it, you need to wait even longer than that so that all of the moisture has had time to be released.
Wipe off all excess grout from the area with the sponge, and wait 15 minutes for the grout to dry. If you see any grout shrink in the areas between the tiles, apply more grout to those areas and wait for it to dry.