We are well into the season for deck collapses. From June to August, we receive the most calls about the catastrophic failure of a deck. It is an all too familiar story of a family enjoying the summer when, almost without warning, they find themselves falling to the ground and covered in debris. The really bad ones sometimes make the news, like the apartment balcony collapse at Berkeley, last year.
Your deck is an extension of your home. However, unlike your living room, a deck is subjected to the forces of nature. The elements, over time, will weaken the structure. Moreover, properly building a deck for the load, wind ratings and local codes ensure a long and sturdy life. Regardless, as a deck ages, problems occur.
When a deck collapses, the first place people question is building codes and if the there was proper permits and inspections. In most cases, it is not an issue of negligence during construction. For example, the Berkeley collapse was dry rot and decay despite the apartment building being only 10 years old.
In North America, the leading cause of deck failure is the leader board. Many times, the hardware connecting the deck to the house fails and the fasteners pull away. The common cause is water infiltration and wood rot. The wood became soft and weak, and fasteners are no longer secure.
Once the deck is not secured to the house, it is a free-standing structure and a hazard. Nonetheless, wood rot is not the only cause of this problem. Sometimes, a crack will form along the length of the ledger board. A staggered bolt pattern limits the potential of this happening.
Another major cause of deck collapse is post and beam failure. Posts that are put directly in the ground, or are not properly maintained, will rot over time. Once the deck has a heavy load, such as a group of people celebrating a birthday, there is a sudden and catastrophic failure.
A final concern is with the deck foundation, which is a problem more commonly seen with do-it-yourself deck builders. We have seen decks on undersized pads, resting on blocks, and just set in the ground. Gravity keeps these decks in place, but even a slight shift can rip a properly secured ledger board away from a house.
In short, older decks have a higher chance of collapse and catastrophic failure. It is important to complete regular inspections and complete regular maintenance to prevent problems. If you would like to talk about the causes of a deck collapse, or need more information, please contact us.