Each summer party season brings a fresh crop of news about deck failures, some of which have ended in severe injury or even death. “These reports send a chill down my spine,” says deck builder Dennis McCurdy, of Littleton, Colo. “What if that had been one of my jobs?”
McCurdy, who specializes in porch and deck replacement, now inspects more carefully, paying close attention to railings and structural connections. “A tear-off [replacing the decking only] works if the structure's sound,” he says. “If it's questionable, and the client couldn't be talked into replacing it, I've simply walked away.”
“Deck-related injuries and deaths usually trace back to two main issues: deck ledger attachments and post and railing details,” says Joe Loferski, co-author of Manual for the Inspection of Residential Wood Decks and Balconies, written with colleagues Frank Woeste and Cheryl Anderson of Virginia Tech.
Ledgers should fasten directly to a solid wood band joist with plenty of lag screws, or, better yet, using bolts with nuts and washers. An even more reliable method is to provide independent posting directly to a solid footing.
Common Problems Few decks the Virginia Tech team has inspected in the past several years had attachment details adequate to support code-specified deck loading, even when new. As nails and wood deteriorate over time, the already-weak connection gets weaker — and while occasional light use by a family may not stress joints to the breaking point, a large summer gathering might. Inadequate footings or post bracing can make matters worse: If a deck sinks at one end or sways from side to side, ledger connections can weaken through fatigue and fastener withdrawal.
For railings, the commonly used half-lap notch at a post base, attached to a deck perimeter with face nails, is woefully inadequate, say the Virginia Tech researchers. The notch weakens the post just where it needs the most strength, and the nails are loaded in withdrawal (a nailed joint's weakest possible loading). Toe-nails commonly used to fasten deck rails to posts typically lack the holding power to resist horizontal forces on the rail.
Limiting Liability Inspecting a deck for the likely typical flaws —deteriorated wood and fasteners, bad flashing and water damage at the ledger connection, insufficient ledger attachment, and weak post and rail details — is a valuable service to a prospective customer that can lead to increased business for remodelers. But such an inspection may also be important in limiting contractor liability. “A contractor has an obligation to evaluate the un-derstructure to make sure it can carry any decking he installs,” says remodeling contractor and construction attorney Quenda Behler Story, of Okemos, Mich. “And if a railing is questionable, a contractor has an implied duty to bring this condition to the attention of the owner.” Story recommends drafting a letter that explains the condition of the structure and that states the owner has been made aware of it but wants you to proceed with the work. The owner must sign off on the letter and be given a copy.
The only time you might need to refuse a job, Story says, is if the deck is in questionable condition and there's a chance of severe injury or death of a third party (not you or the owner). An underbuilt second-level balcony or hillside deck would pose such a risk. “If an owner won't address the problems and there's a chance of someone [dying], you don't want anything to do with that job,” says Story.
Deck Inspection Resource Available from the Forest Products Society ( www.forestprod.org/shop), Manual for the Inspection of Residential Wood Decks and Balconies, by Frank Woeste, Joe Loferski, and Cheryl Anderson of Virginia Tech, covers structural load calculations, footing details, code-required baluster spacing, fastener specifications, and more.