While it isn't a fun chore, maintaining your deck properly will make it look great and last for years. If you take some shortcuts or settle for cheap stains and sealers, you'll have to refinish your deck each year or have it age prematurely; and no one wants that!
The first step to maintaining your deck or wooden patio is to make sure it's sealed as soon as it's built. Even if you have pressure-treated wood, it's more vulnerable to UV rays if it hasn't been treated with sealer. The sun's harsh rays can make wood fibers lose their bond and start deteriorating, so sealing early will help you get more years out of your deck. Prior to sealing your deck, you should ensure that it is thoroughly cleaned.
There are two forms of deck cleaning: a superficial cleaning to remove any dirt or residue on the surface, and a deep cleaning required before you seal it. The deep cleaning often removes the top layers of the deck including paint, old stain and any decaying wood. While many opt to use a pressure washer to do this, if you're not careful you can easily damage your deck. Deck pressure washing requires the right pressure wash tip, the right amount of pressure and a professional touch, otherwise the result is a "fuzzy" looking deck that needs to be sanded as well as re-stained. Scrubbing your deck by hand may be more time consuming, but it's safer for your deck and won't require additional sanding.
If you use a deck cleaner with chlorine bleach as an ingredient, then cleaning your deck can be potentially harmful. Use oxygen bleach instead – it's safer for your deck and for any surrounding vegetation. It's an environmentally friendly way to restore the original color of the wood.
The whole reason to seal your deck is to make sure it can withstand the elements and look great for years to come. So it makes sense to choose a deck stain or sealer that resists mildew, won't fade easily in high traffic areas, and repels water and UV rays. Darker shades of deck sealer offer more protection against UV rays, but cover up the amount of wood grain that is visible. They are recommended for heavily weathered wood, since it will completely cover and protect any damaged wood fibers and make your deck appear to look much newer than it is.
For optimum results, you should always sand down the deck before doing any staining. A light sanding is all that's required for a new deck; weathered decks may require heavier sanding to remove any splinters or peeling deck paint. Make sure to wear a safety mask when sanding. It's ideal to have at least two days of dry and moderate temperatures for the deck sealer to dry fully.