Sweep the deck free of all debris using a broom.
Blow dirt and debris out of the cracks between the wood planks clean using an air pump.
Brush the sealant onto the wood in even coats, saturating the wood until the shade of the wood turns from the natural dry color to a dark, wet color. Brush completely until the wood consists of an even dark wetness free of dry spaces. One gallon of sealant should cover up to 800 square feet of deck surface.
Allow the sealant to dry for 72 hours.
Brush a deck preserver onto the sealant in even coats. While some sealants protect the wood against moisture and sun, you can further protect your wood by layering the sealant with an oil-based wood varnish like polyurathane. Polyurathane provides protection against foot traffic while also deepening the shade of the wood, bringing out the wood's natural luster.
Allow the varnish to dry for 72 hours.