It depends on the caulking type:   The Silicone sealant we use: Adseal series 4580 takes 24 hours to cure. It's fast curing process is extremely convenient and is yet another benefit of the many benefits of this excellent product you can read about here.   Polyurethane generally takes between 48-72 hours to cure. To learn about the different types of sealants click on this link (link to silicone sealant vs acrylic, polyurethane...etc page)