When Bad things happen to Good houses

So... we've known since we bought our house that the back door leaked a little. And it was obvious there was a little water damage. I'd been kidding myself for some time that it wasn't really that bad. But I knew I had to at least patch up the weather stripping this fall, so I decided to take the one door off to have a little look-see




As I took the door off and pulled up ever so gently on the threshold, a whole big 4"-5" chunk of "everything" basically came off in my hands.

Turns out it's rotten down to the rim joist. :-(




So yeah, that's the foundation wall down there at the bottom, and what's left of the subfloor, and what would have been the bottom of the jack stud and the end of the sill plate. At least there's no sign of water down below the rim joist. But because the rim joist is a microlam beam (think plywood) the top 4-6 inches are just dust now, as the water penetrated the laminate and glue layers.

I haven't quite recovered from the shock and not sure what I'm going to do. For the moment I've patched up the gaping hole as best I can with some scrap lumber and a whole mess of caulk.




But now I'm left knowing that there's nothing underneath that patch but open air.

We had a quote from Renewal by Anderson for installing a new sliding door (not French) and it was north of $6k - and that was assuming that everything below the trim work was "basically sound".

I'm thinking come next Spring, I'll start tearing it apart and rebuild it, maybe tie a new pressure treated 2x12 joist to the rotten one, tear out that chunk of subfloor, etc. and get a new door (Home Depot special?)

The moral of this little story: don't ignore little signs of water penetration!!!!