1. Wriggle the railings. No kidding. If you can move them much, they aren't secure. While you're at it, make sure they are up to code, which usually calls for a railing at least 3 feet high with balusters placed no wider than 4 inches apart. Nail or screw loose pieces back into place, use glue for extra security, or replace them.

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Carefully examine deck to make sure it's safe.

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Look for decay. Use a flat head screwdriver to check for rotted wood. If you can insert it more than 1/4 inch into any cracks, or if the wood feels soft or breaks without splintering, you may have rot. Look for holes where bugs may have burrowed in. Replace wood as needed.

Make sure flashing is tight. Flashing keeps water from building up around the ledger board. Make sure it hasn't pulled away from the house and that caulk seals on overlapping pieces are intact. Inspect for debris between the flashing and the house.

Check the house connection. The ledger board is where the deck connects to the house. Make sure it is solid and attached with half-inch stainless or galvanized steel lag screws and through bolts (not nails). Make sure the board is tight against the house. A gap may indicate the bolts need tightening.

Support posts should support. Look for loose connections between posts and deck beams. Tighten and replace bolts as needed. Posts should be 6 inches square or larger and no taller than 14 feet.

Make it pretty. It will last longer if you maintain the finish. Look for mildew or areas where water doesn't bead up on the finish. Power wash the deck with deck cleaner or a solution of one part bleach to three to five parts water, and laundry soap. Let it dry before applying a new layer of penetrating waterproof finish.

Source: "This Old House" magazine, May 2008, thisoldhouse.com