From Big Timberworks:
"The Knee Braces, Window Headers, Loft joists and Trellis posts, plates, Posts and hallway joists all came from the Pioneer Grain Elevator in Southey, Saskachewan, seen being taken down in these photos...

A little later.....

Four of the "principal rafters" (8x20x31, 8x20x29, 8x20x19 and 8x20x14) were cut from a huge timber that came from a house mover in
Minnesota.  I've tried to research this more, but the son of the mover who purchased these big timbers won't return my calls.  The guy's
father bought these old Doug-fir timbers, had 'em shipped from the west coast, and used 'em to support houses as they were moved
to their new locations.  I guess he only used 'em a few years, then bought steel I-beams instead, and left the timbers in a barn for years
and years before the son decided there might be a market for them!  (no photos available)

More "principal rafters" (8x20x27, 8x20x22's, 8x21x21, and 8x20x18) came from the Port of Portland, Terminal #4 Building.  The buiding where the timbers came from is pictured just above the tugboat; it's a long flat warehouse (see below) constructed in 1919.  They've been sitting in our yard for 3 or 4 years since its 1999 demolition.

    The 10x10 "posts" came from a recent demolition in Seattle on Terry Avenue, and I haven't yet researched this one.   All I know is that the building was most recently (about one year ago)used by the City of Seattle to stable its police horses.  Before that, "it was used by some sort of mad scientist," says Jake.  He did some sort of experimentation on magnetics and electricity, because there was all sorts of strange machinery still there, and Danger! high voltage signs posted.  Jake thinks it was built around the 1920s, and he suspects it might have been originally built as a stable...just a feeling he got from the place.  He's doing more research and will let me know.