We are told there are 40 million decks in this country, only half of which are code-compliant. That doesn't mean they are going to fall down. It just means they weren't built to the load-carrying safety standards that municipalities impose today.

In our experience, the overriding issue is the condition of a deck, not so much the codes it may have met when it was built. Decks are a growing focus area in some cities because in mature neighborhoods, younger families replacing original owners tend to populate their decks with bigger and, shall we say, rowdier, crowds. Here are five examination points to help ensure that your deck provides ample and satisfactory service:

1. Wood decks typically are made of columns, beams, and joists married together with nails, screws, and bolts called wood fasteners. Check this hardware to be sure it is not compromised by rust, damage, pullout, or misalignment. As your experience permits, see whether the nail count looks about right (for example, one 10-penny nail can hold up to 90 pounds, which in some cases may be about what the structure itself weighs, leaving little to hold people).
   
2. Check the nuts on the bolts to be sure they are tight. Wood shrinks as it dries, allowing nuts, screws, and nails to lose their grip. What was once a tight connection may now be very loose. Push on hand rails and stairs to monitor movement. There should be little to no wobble.
   
3. Use a bubble level or string and torpedo level to check align-ment. If the walking surface changes by more than a half-inch in 10 feet, it needs to be realigned. Misalign-ment often indicates failed foun-dations. Deck columns should bear on a raised footing that keeps them out of the water, but many are buried in earth or concrete. Check for rot at the column interface point.
   
4. Wood rot is an exposure- and time-related condition. Using an ice pick, randomly stab each structural member. The pick shouldn't penetrate more than 3/8 of an inch deep with a single stroke. Often surface wood hides rot, and it's not unusual to see an ice pick go all the way through a seemingly solid board. (See photo.)
5. Monitor cracks. As noted, wood dries as it ages and small cracks open to become more prominent. This lets water in and loosens knots, which may reduce a board to half its section properties.

In closing I would emphasize this point: The ledger beam is the member that joins the deck and house. Make sure it isn't rolling out or separating from the house mounting point. Ledger connections are the most common failure point of a poorly built deck. It's very important to use lag screws or through-bolts, rather than nails, to secure the ledger. If you have a nailed connection there, correct this situation as soon as possible.