This whole thing is great to pick away at, and probably needs to be done so folks can get on the same page about what a CG is and isn't. I'm not the expert on CG, but I've spent considerable time since joining the forum examining them (like picking barns for the recent tour, etc)... so here's my take:
CGs don't have or weren't:
continuous plates
built or raised as longitudinal bent sections
if [b][b][b]major [/b][/b][/b]rafters they do not bear atop wall plates
They do or can have:
interrupted plates --these must span the width between bents. Scarfed plates are not "interrupted plates"
no plates
A top girt as principal bent connector
if major rafter, they are directly atop crossties
crosstie is directly atop post
principal wall bents obviously raised transversley
In short plate location is not the determinant. Rather plates must be inturrupted in a manner other than scarfing. The plates usually serve as nailer for roof decking/ wall sheathing rather than frame stiffening.
Like I think you said earlier, a CG is basically an English tying joint w/out the plates... I think this is pretty accurate. The only specific, is that if it is a English tying joint with plates, they must be clearly inturrupted (wholly between the crossties).
how's that...?
For me a true CG has no plates at all... the CG (connecting girt) is clearly dropped, and the building has a major rafter/ purlin roof.... just like the first two we saw on the tour.
