Some decks need major overhauls after less than 10 years. Others stay strong and good looking for decades. What's the secret? Well, besides the obvious first choice of suitable lumber (we recommend either a naturally durable species or preservative-treated lumber), a lasting deck is put together with strong, durable fasteners, and it gets regular applications of a penetrating finish to repel moisture and to minimize the effects of the weather.

Although the structure of a deck is a lot like the skeleton of a conventionally framed wood house, a deck doesn't have the stability of sheathing, and there's no roofing and siding to protect if from the elements. That's why decks require extra care and attention to detail. As wood researchers at the U.S. Forest Service Products Laboratory, my colleagues and I have studied lumber, construction techniques, fasteners, and finishes. From this research, we offer some recommendations for building decks that last.

Start with good connections- In wood construction, connections often limit strength: so many common failures of deck construction lead back to connection performance. Proper connections of deck joists to beams, beams to posts and decks to houses are critical.

Because fasteners and hardware in wood decks can corrode, it's prudent to minimize dependancy on them. Wherever possible, joists and beams should bear directly on posts. This type of connection requires more vertical space, but it's more reliable than transferring load through fasteners.

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