Great research. I've been involved in the recreation of the Long Wittenham hall ( pic below) based on the original footings and there would also be a practical benefit in reducing drafts especially if placed to overlap the eaves the walls meet the roof?

Know the feeling! This mosaic from Sanliurfa in Turkey is a new one to me- 5th/ 6th century and depicting a (possibly) Germanic infantryman. Would you happen to know the context of this mosaic and what else is depicted?