Q: Our redwood deck is looking pretty sad. It’s time for a good cleaning and refurbishing. I’m a longtime reader and know you’ve written before on the care and maintenance of decks. Could you refresh my memory?
I seem to recall your recommending a pressure washer, but honestly I’m a little afraid of doing some damage. Is there another way?
A: Every year around this time, we get questions from readers who want to know how best to care for their outdoor wood, whether it’s decking, fencing or siding. With the warm weather here, a quick refresher course is in order.
For longevity as well as aesthetics, we prefer to apply a preservative to outdoor wood. It can either be semitransparent stain or clear preservative. While stain will change the color of the wood, a clear preservative will darken and enrich its natural color. An example is redwood, which is a light red, almost pinkish color in its freshly milled state but turns to a deep red rose when treated with most preservatives.
To look their best and prolong their lives, decks should be cleaned once or twice a year. Frequency depends on exposure to weather and use. A maintenance program consists of cleaning the deck, removing any mildew and applying a new coat of preservative.
Although we continue to believe that the best way to clean a deck is with a pressure washer, a stiff-bristle brush and plenty of elbow grease will do the job, especially if cleaning is done regularly. Think about going to the dentist to have your teeth cleaned. The job is a lot easier and less painful if it’s done every six months.
A pressure washer sends out a pressurized fan of water that makes short work of surface dirt, mold and mildew. These machines are available at rental centers and can be purchased at home centers. If you get along well with your neighbors, consider getting two or three of them to chip in on buying one and then sharing it.
We recommend using a pressure washer that can produce a stream of water of at least 1,500 pounds per square inch. Be sure to keep the wand moving so you don’t blast softer wood away from the surface and leave a rippled effect on the deck. Deck cleaners formulated for use with pressure washers are available where the machines are rented or sold.
If you go the brush route, use a stiff-bristle brush and deck cleaner mixed in a bucket of water in the proportions the manufacturer recommends. We like to use a brush attached to a broom handle to save wear and tear on the back and knees.
In shaded, moist areas, mildew can be a problem. Wash with a weak bleach solution — 1/4 cup of bleach to a gallon of water — to kill the fungus before pressure washing or scrubbing.
Once cleaning is completed, thoroughly rinse the deck with clear water and allow the deck to dry for several days. Then apply two coats of UV protective water-repellent sealer or stain.
It’s a fair amount of work, but worth it. Choose a warm day to do it and the load will be lightened.