Building Code Change to Prevent Deck Collapse / by peter podlas

Deck connection failure at house exterior wall.

Deck connection failure at house exterior wall.

More than a million decks are built and replaced each year in the United States. While decks are a popular feature of many homes, the construction and safety of decks have become a real concern within the building industry. Improper deck building has resulted in a growing number of deck failures with related injuries and deaths. Consequently a code revision was needed.

New York Residential Code has not fully adopted changes within The International Residential Code (2015) currently, however these new changes contain more specifications to build a safer wood deck. The main concern is the deck ledgers connecting to the existing house. As you can see in the photo, the overall deck is intact but the connection between the deck and the house is where the failure occurred. The new International Residential code change wants to prevent the deck from pulling away from the house.

One new approved solution uses a Simpson DTT1Z “L” shaped connector on the underside or the face of the deck joist using lag screws with a washer into the 2x4 stud wall. A minimum of four connectors are required – (2) located within two inches of each end of the ledger with the other two evenly spaced in between. This new connection detail will not allow a deck to collapse as shown above.

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