Decks of all sizes are affected by weather conditions over time, and if not properly treated, they may have warped or rotten wood that needs replacing. Structural integrity is the most important factor to address, along with the tread boards that carry the majority of the weight when the deck is used. Check your deck each year, preferably after the colder fall and winter months have passed.
Check the Decks Framing
Look at the structural framing underneath the deck's tread boards. Closely inspect all vertical and horizontal support beams and posts, making sure they are not damaged or rotten. If they are, cut new lumber to the same measurement as the old wood and use new bolts, screws or nails to attach them in place.
Check the Concrete Footings
Study the concrete footings where the vertical posts meet the ground. The posts should be secured to the footings with 1/2-inch-diameter bolts or larger, with the nuts securely tightened in place. Galvanized nails in addition to bolts are sometimes used to secure the posts to the footings. Ensure there is no earth-to-wood contact around the footings, as this may rot the bottoms of the posts. If any exists, remove all dirt or debris with a brush or trowel.
Check the Tread Boards
Check both the underside and the top side of all tread boards, first for any warping or rotting. Replace boards that are not in good shape. Look on the tops of the boards for any loose deck nails or screws. If loose screws are in good shape, re-tighten them in place, and if there are any loose nails, replace them with good-quality deck screws, 2 1/2 inches or longer. Also check all areas of the side rails for warped or rotted wood and loose nails or screws, replacing any that are found.
Repaint/Stain the Deck
If the paint or stain covering all parts of the deck is beginning to flake or fade, clean and scrape the deck with a high-pressure water hose or an oscillating tool with a sanding accessory, and repaint or re-stain the deck.