Hello GtMerkley,
Well, that is a relatively common challenge with older barns...especially if it has gone through a spell of "disrepair."
First, I want to be very encouraging, that these old structure are often more than repairable. I grew up working with Old Order Amish Barn Wrights not to far from you just North In Charleston, Il back the 70's and 80's...so have seen many a barn and repaired then...
Now...for the next part of this post...that may not sound so helpful...
As a Traditional Barn Wright...and...now relatively well heeled general Timber Wright...I would be doing you a disservice if I didn't speak honestly (as I have come to learn it in my experience with historic buildings) that it is really difficult to provied solid (and safe) advice for such repairs without actually seeing the structure and all the mitigating condition that very well could be affecting the frame...including things that can go awry because of or during the repair....Pictures at minum is a "must have," to even begin any rational diagnosis and solution advice.
...DISCLAIMER...I also do tend to lean on the side of caution with such advice as this...as I may or others may share. I have come up with a few "safety margins and protocol" for sharing such guidance in these circumstances...
One of the first and foremost, is whoever is doing the work (or guiding you in the work) should have a minimum of 20 years experience in...
actual....Historical Restoration practices...especially timber frames. There is a huge difference between a "band-aid" (aka temporary ...
"historic conservation work"... that must be reversible without damage to the historic "fabric" of the architecture)....and....(hopefully!!) their work is also backed up (and/or overseen) by structural Engineers (PE) that work on timber frames.
IF...they don't have that type of support and/or background...then, the
PE is a must have or the building and occupants can well be in jeopardy life and or structural compromise before, during and/or after the "repair."
There are many out there doing "repair work" that is anything but "a repair" and is definitely not any kind of grade or form of "historic restoration/replication" in practice or form. We find many of our barns (and historic buildings...thanks to DIYERs and shows like "This Old House") that have all manner of "steel plate"..."chain"..."lag bolts"..."jacks and concrete" and other..."not so nice"... things done to them that may "appear" sound, or..."a good idea"... yet often is nothing more than a "psychological repair"...not a tangible one that actually is structurally taking the proper loads.
I am glad you came here for advice...Good of you to do so!!!
Before I forget...I am putting to organizations besides the TFG you may turn to for additional guidance or supporting advice:
The National Barn Alliance Indiana Barn Foundation So, in closing, feel free to reach out to me "offline" if you care to chat in more detail, ask more questions, or explore this further in other ways...
It sounds like you are on the right track thinking about it, and it is (or sounds?) repairable, but I can't really say without much more detail and documentation/illustration. I can say that the "current repair"...not restoration...approach is probably not how I would do it. I would want to replace the tenon with "like species," have it into good and solid wood, inspect and augment where necessary the receiving mortise and house as this beam appears to be taking more than just tensioning loads...so working from the outside of the frame is also warranted I do imagine...
I do more than understand...budgetary constraints...and as such would probably go with a more robust (Larger) and perhaps "awkward looking" approach call a "conservative strengthening" that is both historically and easily reversible. These often are actually really fast to do, less expensive, but can be "bulky and esthetically" not what folks expect...However, they get the job done and make future..."actual restoration"...much more plausible and/or easy...
Good luck...if you can post picture great...feel free to email or call...
Regards,
j
