A deck ledger board pulled away from the house on a job last Tuesday
I was doing a routine inspection on a deck built about 15 years ago in the West End. I gave the rail a solid shake, and the whole structure moved. The lag screws into the rim joist had loosened over time, and water had gotten in behind the board. We had to prop the deck, strip the siding back, and sister a new treated rim section onto the house before we could re-secure everything. Has anyone else had to deal with a ledger failure that wasn't from obvious rot?
You're missing the whole point of modern building science. Proper flashing, sealed membranes, and drainage planes are designed to manage water, not just block it. Look at a well built brick cavity wall or a rainscreen system. They let water in behind the cladding on purpose and then channel it back out. It's not about being a perfect dam, it's about giving water a controlled path that doesn't lead to rot.