When we first began building residential decks, there was no scientific research that determined we should use ledgers, joists, beams, and posts the way we did. It just happened that we’d want a deck to be about the same level as the home’s first floor, and connecting a ledger to the band joist, with deck joists hangered from its side, seemed to make sense—until it didn’t.

As problems started to crop up with some of our ad hoc ledger connections, researchers and code officials began to pay closer attention to these details. As a result, now we know better than to fasten a ledger over existing exterior cladding or veneer; you’ve got to cut through the cladding to the framing. The ledger flashing can’t be stuffed up behind the siding; no, it has to be laced in shiplap-style with the water-resistive barrier. And no longer is it acceptable to drive lag screws through the ledger into the wall and “call it good” when they snug up. Now, the IRC has strict guidance for spacing between fasteners and edge clearances. And whether you use bolts or lag screws to fasten the ledger to the framing, the inside of the band joist must be accessible to either thread a nut or verify what the lag screw is holding. What about anchored brick veneer, stucco, or adhered stone—how do we get around that? Here’s where we lower our sights—to the foundation instead of the band joist.

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