I can't speak to this from a historical perspective, but I can from an engineering perspective. When you drop the tie beam, even a little bit, you've switched the critical rafter foot connection from a compression joint into a tension joint. Also, the further you drop it, the higher the tension, as the rafter thrust at the post top is acting as a lever, trying to pry apart that joint.

You asked for pictures, and I have some. There are my own work. The client insisted on exactly what you asked for, and probably for the same reason: loft space. I'm sure you'll be able to spot the compromise solution . CB.




CB.