I have recently been playing around with the idea of, instead of joining the floor joists of a loft into the tie beams with dovetail or soffit tenons, just setting them across the tie beams and using the subfloor and finish flooring to stiffen this " floating floor". It would save a lot of time in the cutting of the joints for all of the joists and also save the tiebeams from losing some of that all important depth. Of course I would still engineer the frame to be able to support the live and dead load of this loft. Also, this would allow me to put the floor in later, as time allows, thus simplifying the raising. The only negatives I can see right away are that I would lose a bit of headroom in the loft and perhaps a bit of stiffening effect of the tying joists in the overall frame, both of which seem minor disadvantages compared to the advantages. I originally got the idea as I plan to build a Dutch barn and they always just laid sapling poles across their anchorbeams to support the hay loft and that seemed to be quite effective. If anyone has anything they can expose on this topic that would be great. I am curious if others have tried this as well? tb

I've seen this done in a couple of cabins. One was an older P&B with round loft joists adzed flat on top and where they lapped over the beams. I think they were spiked in place but they may have just been held there by the loft floor.
The other had about 50-60% of the joist above beam level and there were shallow drop in mortices in the beam. It also had a hand carved details on the summer beam and plaster ceiling (except where the roof leaked and it fell).

This is the way Jack Sobon designed the loft of my garage. The joists are just set on top of the tie beams and toe-nailed (square nails) in place.