Just one post in the middle? Side entry or gable end entry? If it is a gable end entry I would see two post under the tie, running the length of the barn, not one post, it would get in the way. But with the 14-8-14 bay layout it appears to be side entry, in the 8' bay. Is there any sign of other members supporting the ties, as example, stall framing, walls, ladders, dividers of some kind?
What is the size of the typical tie beams seen in the old barns?
