Hi Toluca and Mark,

This is a dissertation topic !

Very few vernacular buildings have any form of bracing found on the ground (1st) floor with these components generally being found on the upper (2nd) floor. A sure giveaway sign of an old building is the height of the wall plate which tends to be driven by available post height with this lying somewhere between 10 and 12 feet. The mid (girding) rail is just that - it tends to be set half way between u/s ground sill and t/o wall plate with upper floor joists sitting on top of that rail thereby resulting in quite low headroom on the ground floor (typically 7 ft) with a disproportionately high upper headroom of about 10 ft to underside of collars.

As with everything in life one occasionaly comes across a building that turns everything upside down and this is the case at The Olde Bell in Henley on Thames, Oxfordshire (dendro dated to 1325) where the lower floor headroom [underside sill to top of floor] is 8 ft with an upper floor headroom [top of floor to to top of wall plate] being 10 ft above which soars an open crown post roof.

Good question !

Regards

Ken Hume