Certain sealers contain paraffin wax as a protective ingredient. If the sealer used on your deck contains this wax, you will see water bead for a period of time after the sealer is applied. Other sealers use oils as their protective ingredients. Although decks sealed with an oil-based sealer will not always bead water, they are fully protected from any damage that may be caused by water. Please keep in mind, products that contain a lot of wax will usually cause your deck to darken quickly. This is the result of the sun breaking down the wax thus causing dirt to be trapped in the wax. After one season, your deck will look old and worn out.