Before you start, however, check to make sure your deck is still in good working order. Take a look underneath it to see if the fasteners and connectors are sound. Examine the wood for any worrisome cracks, rot, or mold growth. Make sure the railing hasn’t come loose and the steps are still sturdy. And if your deck is more than 40 years old, make sure carpenter ants and termites haven’t gotten into it. Modern decks—those built in the 1980s or since then—are often made with lumber treated with chemicals that insects don’t like, but older decks are susceptible to their destruction.

Steps for Spring Cleaning Your Deck

Once you’ve confirmed that your deck is structurally sound, here’s how to spruce it up for the season:

Step 1: Wash

Washing a deck in the summer heat can put stress on the wood, so it’s best to wash it in the cooler months of the spring.

Use an oxygenated-bleach cleanser for the scrub-down. Chlorine bleach, even when diluted with water, is very hard on the wood. Don’t use a power washer for this job, as the concentrated spray will be too much for the wood to handle. A soft scrub brush will do just fine. Test the cleanser’s strength in a small area before you start. It should be able to kill the mildew and remove the dirt in 10 to 15 minutes. If it takes longer than 15 minutes, the mix is too weak; if it takes less than 10 minutes, the mix is too strong. Thoroughly wash off the cleanser after you’re done.

Step 2: Sand

When the deck is dry, it’s time to sand it. Before you start, though, make sure every exposed screw or nailhead is safely below the wood surface.

Use a four-head random-orbit sander with 80-grit paper on the decking, and a handheld random-orbit sander along the edges. (Sanding pressure-treated wood requires taking special precautions; check the EPA guidelines.) Sand lightly, and stop as soon as the gray is gone. Make sure you vacuum up all the sanding dust before moving onto staining.

Step 3: Stain

Pour the wood stain you’ve selected into a small bucket, and start by applying it around the edges of the deck using a paintbrush. Then pour some more wood stain into a paint tray and use a lamb’s wool applicator to apply it to the rest of the deck. Use long strokes and apply a generous coating, but make sure it gets spread out well. Allow the first coat to dry for at least 24 hours, then apply a second coat. A semi-transparent stain should protect the wood for two to three years, depending on the amount of sun exposure.