Decks collapse with disturbing regularity. In July, a 14-foot-high deck on a Montana casino gave way, injuring 52. A month earlier, the third-floor deck of a Chicago apartment filled with partying college kids collapsed onto the deck one floor below. That incident killed a dozen and injured more than 40. The same month, eight people were hurt when a deck collapsed in Des Moines, Iowa.

Deceptively Complex Decks look like simple structures. But they're not, and they can't be built safely without proper attention to details.

“A deck is a unified structure,” explains Rick Crossman, president, Archadeck of Southern Fairfield and Westchester Counties. “You can't recommend using this particular piece of material in a given situation, because that's all related to the engineering of another piece of material.”

The first order of business is to get the necessary permits and make sure you're building to code, says Bill Doyle, corporate deck trainer for Thermal Industries, Pittsburgh. “Footers must be set to the proper depth for the area, and you've got to use proper joist spacing and the proper size lumber for the extension out from the house. You can get all that from the local municipality,” he says.

Build For Any Live Load Before designing a deck, Crossman makes it a point to gather all the information he can when he talks to a client. “The best carpenters think several moves ahead,” he says. “You want to look at the whole picture before you start the construction process. Don't skip over information, because you may find you will need it later.”

Doyle adds, “You have to make sure that you are building your deck substructure to support any live load that is going to be on that deck surface. If the homeowner is going to put a lot of things out on the deck — maybe a hot tub — you need to consider that.”

Given certain load requirements, you've always got choices —often many — about how to build to meet them, Crossman says. “There are different ways to do it, but you've got to do it. If you aren't sure, or you have questions about what you can and can't do, it's a good idea to consult an engineer,” he says.