Most deck sealers require at least 24 hours of dry weather to cure. If you plan to apply two coats, you must allow 24 hours of drying time pass before you applying the second coat.hen pressure washing, saturate the deck with deck detergent, give it 15 minutes to work, then begin power washing. Follow the operating directions for your power washer. After completing the deck power washing, wait 24 to 36 hours before applying sealer.