How to Properly Clean and Seal a Wood Deck

D eck maintenance is the thin line between a welcoming backyard retreat and a splintering, rotting eyesore. Wood is a living material that constantly fights against the sun's UV rays and moisture, so treating your deck isn't just about appearances—it's about structural survival. A deck done well looks rich in color, repels water like a waxed car, and feels solid underfoot. To get this right, you have to prioritize prep over product. If you try to seal a deck that is still dirty or damp, you are essentially trapping debris and moisture under a plastic-like film, which will lead to peeling within months. Clean deep, wait for the wood to breathe, and then apply your stain or sealer with patience. If you follow the grain and stay consistent, you'll only need to do this heavy lifting every two to three years.

1. Empty the Deck. Remove all furniture, planters, and grill accessories from the deck. Use a stiff-bristle push broom to clear away loose leaves, dirt, and spiderwebs from between the boards.
2. Lift the Grime. Wet the boards with a garden hose, then apply a sodium percarbonate-based deck cleaner using a pump sprayer. Scrub the boards with a stiff deck brush, working in manageable sections, and let it sit for 15 minutes without letting it dry.
3. Flush It Clean. Rinse the deck starting from the highest point and moving toward the low end. Use a steady stream of water to flush out the lifted grime and leftover soap residue.
4. Let It Breathe. Allow the wood to dry for at least 48 hours. The wood must be bone dry to the touch to ensure it can absorb the sealer properly.
5. Smooth the Surface. Once dry, use a pole sander with 80-grit paper to knock down any raised grain or remaining splinters. Sweep away the resulting dust before starting the seal.
6. Seal It Right. Use a staining pad or a wide brush to apply a penetrating deck sealer. Work in long, continuous strokes along the length of each board to avoid overlap marks.