Deck Care
I have had decks for about 19 years. I have never used a power washer to clean my decks. Why, because power washers raise the grain on the wood. I like the old fashion scrub brush on a broom pole. This has always worked for me.
Here is how I clean my deck. First grab a pair of rubber gloves. I use Tide and add bleach to the water. You can use a bucket or a wall paper tray to mix the detergent and bleach solution with water. It is easier to dip the scrub brush in the wall paper tray than the bucket. However, make do with what you have around the house.
Hose the entire deck down with a garden hose. Really soak it. Then start scubbing from the rails and work your way down to the decking. The moss and mildew will disappear before your very eyes.
Rinse the deck like you mean it. Really give it a hard rinse. Then stand back a take a look at your work. If you find missed areas repeat the wash. Then let the deck dry. This might take a day or two.
I use and recommend Cabot deck treatments. Do your own research; you should arrive at the same conclusion. I prefer transparent stains over solid stains, just my preference. Before you apply any deck treatment read the whole can. Follow the directions. Before making a move, check the internet for a weather forecast. The directions don't tell you what will happen if it rains on your wet stained deck but I will. It may turn the finish tacky as flypaper. This error is fatal for about one year until the deck is weathered again. Don't rush this. Your clean deck will wait until the weather is perfect for a stain application.
Use a 3 inch roller to apply the stain and a cheap paint brush. Have a good size piece of card board handy to use to protect places where you don't want stain to splatter. I also use masking tape to keep the stain off the house.
Start at the top rail and work your way down. Be generous with the stain. Any areas where the roller doesn't reach use the paint brush. The 3 inch roller does a great job on the rails and on the deck. Let the deck dry before it is used again. After 24 hours test an area for dryness. If the deck is still tacky, wait another 24 hours and test again. Always follow the manufacture's direction on dry time.