The addition to the 2009 IRC about lateral load connections for decks is confusing. Section R502.2.2.3 states that the required lateral load connection “shall be permitted to be in accordance with Figure R502.2.2.3,” which shows a pair of hold-downs — one on a house floor joist, one on a deck joist — connected by a threaded rod. The phrase “shall be permitted” is rather abstruse if you don’t have a legal education! Looking at the code, you may think that these hold-down devices are required. Combined with the requirement that the floor sheathing inside has to be nailed at 6 inches on-center rather than the usual 12 inches, this detail makes decks a lot more difficult and expensive to build.
It’s a shame that this clause has clouded the really great advance the code made when it finally included a prescriptive fastening schedule for the ledger. Looking ahead, this code section will most likely persuade homeowners to build patios instead of decks.
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