When balconies and decks collapse without warning, it's terrifying. The disaster in Berkeley, California, earlier this week left six people dead.
It's happened before. In 2003, 12 people were killed in Chicago when a deck fell three floors out from under them.
In December 2013, a family posing for a Christmas photo experienced a terrifying collapse, injuring seven people.
In another incident, students were posing for their prom photos in Indiana when the deck collapsed. They were lucky: they all survived.
Research shows that there is a 50% chance of surviving a third-floor collapse. But there are ways to prevent a disaster.
Structural engineer Chris Krepcio of Merritt Engineering showed INSIDE EDITION'S Les Trent what you need to know to make sure the balcony you walk on is safe.
Every balcony should be inspected annually. Look for the warning signs. With wooden balconies, look for rot and water damage.
There are specific things to look for with concrete balconies.
"What we do typically is a visual test. We'll see if there's any cracking, any areas that are obviously deteriorated," said Krepcio.
"We want to check the connection between the concrete balcony and the building," he said.
Two years ago, a New York City woman fell to her death when a guard rail gave way. She was on a first date.
"What sorts of things are you looking for in terms of safety when you're talking about a balcony?" asked Trent.
"The first thing we look for is the railings. Typically, we'll shake it. We'll put a pretty significant load onto it. Also, we'll check the base plates and make sure they're properly secured," said Krepcio.
Perhaps the most important thing to remember is too much weight on a deck or balcony can lead to disaster. That's what appears to have happened in Berkeley. As many as 13 people were jammed on the small balcony when it collapsed.
"There are certain things you can do, in terms of making sure you don't have too many people on the balcony. Is there any hard-and-fast rule?" asked Trent.
"We typically say if you put your arms, we use what we call the 'elbow rule.' If you put your arms [up and bent at the elbow] and you're touching somebody else, you probably have too many people," said Krepcio."
Experts say you have to use common sense, including "understanding that a small balcony shouldn't hold 10, 15, 20 people," said Krepcio.
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