Here’s where I really need guidance. This drawing is an elevation view, so as if you’re outside laying on the ground looking at the corner of the house.
Getting the old 2x8s out isn’t an issue. They’re primarily sawdust. My concern is that the sawdust may be providing just enough support to prevent the wall from crumbling. I have a plan to repair it, but not support it during the repair. Basically take it all out and replace with PT lumber, but if I take out the compromised rim joists, will I risk having the whole corner of the house fall off? I would be removing about 12′ under the E/W wall and another 12′ on the N/S wall.
Can you folks take a gander at the only thing I can think of and tell me if I’m crazy?
In the next photo, the yellow would be 2x6s screwed to a stud in the wall, and under a ceiling joist or rim. I would likely use some HeadLok screws I have an I wouldn’t be shy. The red squares are bottle jacks on a paver with a scrap of ply. Once supported, I could rip out all the compromised wood and replace it. This idea at least gets the support jacks out of the plane where I need to replace lumber. Does that sound safe?
Important to note. According to the wonderous rotating laser, the corner you’re looking at is about 1″ lower than the highest point in the floor, (which was about where I’m standing for this photo) but since I lowered that high point about 1/2″, the corner is actually only about 1/2″ lower than my target joist height.
So that begs the question. I could
A) replace both the rims at their current height, replace the joists, and painstakingly shim the entire room (sounds like a recipe for a noisy, weaker subfloor)
B) replace both the rims at their current height, but notch the top of each span joist so I can clear the sill and install 1/2″ higher to my target height
C) use the bottle jacks to lift the whole corner 1/2″ and sneak the rim under it at target height before installing new span joists.