Do It Yourself: Special Care For A Redwood Or Cedar Deck

Do it yourself instructions provided to help you with the special care needed to clean and maintain both redwood and cedar decks.


When your redwood deck becomes dull and gray it is time for a good cleaning to revitalize the wood. Examine the redwood deck carefully to see if you are dealing with any rotten boards. It may be necessary to replace the boards if the rot is more than ½" into the wood. Using a flat pry bar, carefully remove the rotten boards and replace with new redwood boards. Any nails that have worked themselves loose should not be pounded back into place but should be removed and replaced with special decking nails or decking screws.

Sweep away any accumulated leaves and surface dirt, paying special attention to the dirt between the boards. If your deck tends to stay wet in places, take steps to remove the offending bush or tree that may be causing excess moisture on the deck. You may need to re-route the direction of a gutter downspout away from the deck.

Mildew on a redwood deck is usually seen as a dark, black stain on the wood. This black stain can actually adhere itself to your clothing or shoes. A mildew problem created by wood that is allowed to stay wet can be treated with a good chlorine bleach cleaning, but unless you solve the issue of what is actually causing the wetness, you will not be able to prevent future mildew problems.

To clean your redwood deck, there are three main categories of commercial cleaners available. They are chlorine bleaches, oxygen bleaches and oxalic acid-based formulas. If using chlorine bleach, be sure and pre-test in an inconspicuous part of the deck to make sure it doesn't remove any of the color from the wood. These formulas can be pressure washed onto the surface of the redwood. Follow the manufacturer's instructions on the back of the cleanser and as always, wear appropriate clothing, especially if your cleanser of choice is acid-based.

Once you have thoroughly cleaned your redwood deck apply a good synthetic sealer which contains water repellant. Synthetic sealants including penetrating finishes include oil-based water repellants, oil-based semitransparent stains and water repellent preservatives. The sealants also contain mildew-cides and algae-cides and UV-blockers to promote the graceful aging of redwood. Apply the sealant using a brush, paint roller or sprayer.


Cedar is a richly colored wood that is a member of the cypress family. Cedar decks are popular because like redwood, cedar is naturally rot-resistant and can last anywhere from 10 to 30 years. You do not need to seal a cedar deck to prevent rot, but to keep the wood looking natural and to help prevent it from turning dark or gray it is a good idea to use a sealer with UV protection. Use a sealer with a penetrating capability made especially for cedar decks. Cedar is naturally lighter in color than redwood and therefore the staining options are limitless.

Pressure washing a cedar deck can cause the deck to look gray and fuzzy. This is caused by the impact of the high-pressure water tearing at the wood fiber of the cedar. A stiff nylon brush can be used to remove the fuzziness but you may have to resort to sanding to completely remove it. Make sure the deck is completely dry and then start with a 40 or 50 grit sandpaper and work up to an 80 to 100 grit paper. Remove the sawdust with a dust mop and then follow by blowing the wood free of grit with a leaf blower or similar air blower to make sure the cedar is as clean and dust free as possible. Follow by applying either a sealer or a penetrating stain with UV protection. You may need to apply two applications of the stain to properly color and treat the deck. A fresh application of the stain should be applied every two years to maintain the fresh appearance of the wood.

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