Hey Shawn:

Some of these dropped tie-to-post connections had dovetailed or wedged tenons on the end of the tie beam, usually w/ a angled haunch cut into the post.

The dropped tie is not the best in my opinion. I've seen some barn books speak to this area/design as prone to failure.

Just a atraight tenon and a couple of pegs is really asking for trouble on this type of joint. Can you say "withdrawal?" Anyway, take another look at that particular barn and see if the tenon isn't wedged...from the outside under the sheathing if you can get to that area. Maybe it needs a new wedge (I know, too simple, right?)

Here's Sobon's book you mentioned. It's availible on the Guild's site as a PDF. Look at the dovetailed/wedged tenon (pg. 4) http://www.tfguild.org/joinery/part1.pdf


As far as guarding against future wall spread, once you get the walls back to plumb, or close, perhaps inserting some sort of ridge support is part of the overall plan? If the ridge can't sag, the walls can't spread. Maybe a number of vertical ridge supports is an option.