i don't think hewing only one side is beneficial... doesn't that incur differential drying? (unless you wanted the timber to crown...) isn't this the the 'sponge that is wet on 1 side' curling up problem? wood likes to equalize - unless you are cutting FOHC from really large trees (or small pieces from smaller logs) - boxed heart would make the most sense to equalize the drying forces and balance out the sapwood to each side of the timber... no?
2 of the barns that i surveyed and moved had 'sleeper' joists for the first floor - hewn 2 sides -top and bottom. bottom was pretty rough - top was 'flat enough' for the floor boards to go down on. the barn we used as a shop had 3/4 rounds in the floor - hewn only on the top, 'flat enough' for the floor above. another large barn in PA we dismantled had pole rafters, but hewn timbers.
i'm not sure if 'the old timers' - masters and ideal builders as some want to hold them up to be - had a consistent system for this. it certainly would seem to vary by region, species available, and size of logs.
