It’s a good idea to reapply stain once a year on wooden decks, especially if the deck is located in full sun most of the time. The sun’s ultraviolet (UV) rays are one of the most harmful environmental factors for wooden decks. UV rays destroy the lignin in wood that holds cellulose fibers together. This causes the fibers to eventually wear away. Better quality deck stains have UV inhibitors that either reflect or absorb the sun’s damaging rays.

Water is the other environmental factor that destroys wooden decks over time. When not protected properly, wooden deck boards absorb water and expand and shrink across the width of the deck boards, especially at the ends of the boards. Quality deck stains contain penetrating finishes to slow the water absorption process.