Steve,
I am very familiar with the type and style of barn that you are looking at replicating. I have restored and even relocated a few of these TF barns in Wisconsin.
I agree that the driveway mow/bay was used as a threshing floor where the oats, wheat, or barley was thrashed with a flail to loosen the seeds from the hulls. Often times there would be a smaller door, or set of doors on the opposite side of the barn from the large driveway barn doors, that when the wind would blow, the chaff would be separated from the seed by tossing the combined mixture into the air, and the wind, that was passing through the barn, would carry the chaff out the door and out of the barn....this is called winnowing.
The short wall on either side or the threshing floor did keep the hay and straw off the threshing floor and gave a surface in which to scoop or shovel up against when collecting the grain.
The threshing floor was only used in the early part of the growing season since winter wheat is planted in the fall, grows in the spring, and is harvested before the first hay crop is ready to be acut by early summer. Some of the hay and straw from the previous season would probably be left over from the winter months, since the pastures would not be able to sustain and animals until early summer.
The floor support system for the driveway mow/bay is in a different orientation than the end bays for a couple of reasons.
First, the floor boards would run perpendicular to the threshing walls so that the grain could be swept/ scooped towards the wall without going cross grain to the floor. And the outter floor board that would be just inside the barn doors coul be replaced easily if it were damaged by exposure to weather, work horses, or wagon wheels.
Second, often times the width of the threshing floor would be divided into three seperate spans for the floor joists, which would shorten the length of the joists needed and helped to stabilize the floor with less flexion, or bounce.
At the last public barn raising that I co-hosted, of a barn that was originally built in 1888, we pre-assembled the 6 bents and stacked them in the order that they would be raised. #1,#2,#6,#5,#3,#4
They are assembled and stacked in reverse order with the reference faces facing up. Just like the trunnels that connect the girts/siding nailers to the exterior bent posts, being driven fom the ouside/reference face....so to the trunnels that are used to build the bents are also driven from the reference face.
The stone foundation probably does reach down below grade but how far is anyone's guess. I would recomend pouring a concrete frost wall below final grade...24in wide with a even wider footing underneath...and then build your stone wall on top...no one will know, and we can all keep a secret! haha
Rooster
