Is Your Deck Safe?
Protect yourself from collapse, rot, and nasty splinters. Inspect these 8 critical areas every season.
With 40 million decks in the United States that are more than 20 years old, there are plenty of families whose outdoor fun is resting on a shaky foundation. At least 30 people died as a direct result of deck collapses between 2000 and 2008, according to the North American Deck and Railing Association, and every year, many more are injured in deck-related accidents, many of which could be prevented. An annual deck inspection takes less than an hour and could head off a catastrophe. Here’s what to look for.
The ledger board, where the deck attaches to the house, is a common site for deck failure. Check the connection between the ledger and the house, especially if your deck is more than 3 ft. off the ground, in which case a collapse could lead to serious injuries. Ledger boards must be bolted or screwed securely to the house, not just nailed, because nails tend to pull out. The 2009 International Residential Code (IRC) has a prescriptive lag-screw and bolting chart that gives some guidance for adequate fastening and fastener locations. For example, the code calls for a 12-ft.-deep deck to be attached with 1⁄2-in. lag screws spaced 15 in. apart or 1⁄2-in. through bolts 29 in. apart.
Also, look for rot in the ledger board and the wall behind the ledger. Water often leaks behind the ledger board due to improperly sized or poorly installed flashing, even on recently built decks. Decay in floor and wall framing weakens the holding power of the bolts and screws to the point where they can pull through, allowing the ledger to come loose. Check for signs of water getting behind the ledger board, and probe the area with an awl or a small screwdriver for soft spots that indicate rot. The deck ledger and possibly the entire…