Applying your deck coating
Determine if your surface needs to be sealed. Pour a cup of water onto the surface. If the surface darkens or the water is absorbed in less than 10 minutes, your surface should be stained or sealed. If the water beads on the surface or if it is not absorbed in 10 minutes, the surface is not ready for sealing. If you want to proceed, you will have to remove the old stain or sealant before applying the new.
If necessary, remove the old coating with an appropriate chemical remover.
Clean and prepare the surface thoroughly. Fix damaged areas of the surface. Cover anything in the area that might be delicate, such as plants and other ornamentation. Remove debris from the surface with a push broom. Apply an appropriate surface cleaner and rinse off when finished. Allow 24 hours for the surface to dry completely.
Clear the area surrounding the surface you will be coating. Cover with a drop cloth to account for dripping and accidental spraying.
Check the weather. You shouldn't coat your surface in direct sunlight. Make sure the temperature will be between 50 degrees and 85 degrees Fahrenheit, and there will be no rain, for the entire drying time of 24 hours.
Apply the coating to a small, inconspicuous area and allow it to dry completely. This is to ensure that the coating creates the effect you desire and won't damage your surface.
Apply a thin coat with a brush, roller or sprayer. Make sure to cover all areas of the surface, including joints and corners. For best results with a brush, use a back-brush technique.
Allow your coating to dry for 24 hours before replacing furniture and walking on the surface.