Thanks, Don. I agree, that bridging would be a good idea. The center girder has only dropped an inch and a half in all these years. I have jack posts under the first floor girder (in the cellar)and I plan to take a closer look at the support posts for the second floor when I get the ceiling opened up. I'm thinking it may be a little easier to work on this repair from above, though. But in any case, I have to redo the ceiling, I can't believe they used 2x4s to support it!