NASHVILLE, Tenn. -- If the rain lets up and you plan on spending the rest of your evening on your deck or porch, should you be concerned about its stability?

Related: Video: Deck Collapse Demonstration | Deck Safety Checklist (pdf) | Inspector: Thousands Of Problematic Middle Tenn. Decks

"I was actually hanging from the rail, just standing there, and everything just started sliding. Everything goes down," said the victim of a balcony collapse. "I landed in the back corner, actually on top of one of my friends from school, and he broke his hand."

A group of men fell when a balcony collapsed at a Nashville apartment complex in October.

The cause for the broken bones and injures was that the balcony wasn't properly fastened to the building, according to the Metro Codes Department.

A certified home inspector said it isn't a question of if this will happen again in middle Tennessee but when.

"I can show you thousands of decks in middle Tennessee that are very similar to the problems that these decks are having," said deck inspector Dick Schor.

In just one day in Nashville with Schor, the Channel 4 I-Team found more than a dozen decks and balconies that Schor said were so unstable, no one should use them.

Decks and balconies were supporting hot tubs, grills and children.

"On a scale of one to 10, one being good, 10 being awful, you would not catch me partying on this deck," said Schor.

Inspectors all over the country are now worried about the decks many own. A national non-profit deck safety group recently met in Atlanta to outline why so many decks are just now failing.

The main issue is age.

"It is estimated 40 million decks in the U.S. are over the age of 20 years," said Bobby Smith, president of the North American Deck and Railing Association.

Many decks found in the Harpeth Trace subdivision, for example, were built to code at the time but don't meet today's safety standards. They're not properly fastened to houses or don't have the correct footings.

Metro Codes said the balcony collapse previously mentioned happened because nails were used instead of bolts. Again and again, decks found in Harpeth Trace were secured to houses with nails.

Schor said the major concern was collapse.

Not only nails were starting to come loose on one deck but so was a support beam standing on a piece of loose wood.

"I would tell them not to use this deck," said Schor.

It isn't only the support of the decks that's a problem; it's the railings. Some porches were found where vegetation had pulled railings apart and where shoddy construction had caused banisters to fall apart. One apartment complex balcony was bowing in the middle.

"Is that a concern for you guys to see it like that?" asked Channel 4 reporter Jeremy Finley.

"I would think it might be," said the apartment complex maintenance supervisor.

At another balcony, on which a girl was playing, the railing had been damaged by water so badly it was starting to look puffy.

"It wouldn't take very much for the railing to collapse," said Schor.

Some of the worst decks found were behind some of the nicest homes in Brentwood.

Schor was able to move entire decks with just a slight push, thanks to weed-whackers damaging posts and nails coming loose.

When stairs that were coming apart were pointed out to one of the decks' owners, he responded, "I didn't notice that. That's a concern. And we will have to repair that."

Schor urges people to have their decks inspected.

"Decks never fail unless there's a celebration," said Schor.

Related Link:

Deck Safety Checklist (pdf)