Restoration
Redwood is the premium choice for decks for many reasons, not the least of which is its ability to be repeatedly restored at minimal effort and cost. How often you do, though, is largely a decision of aesthetics. Many owners will decide to restore their deck when the original bright color of the wood becomes duller and grayer.
There are many methods and techniques to consider with each deck before beginning the restoration process: age of the deck, quality of redwood, orientation to sun and shade, exposure to inclement weather, to name a few. The general steps taken to restore a deck can be performed by application of commercial products, often called deck cleaners, brighteners, or restorers. These products do not add color to the deck, but will remove mildew and dirt, allowing the natural color of the wood to show. After proper drying, a finishing stain or water repellent can be applied if desired.
As always, if in doubt about what step to take, consult with a reputable, well referenced, professional who has “seen it all” and can gauge the best approach you can take with your deck.

