TIMBER FRAME VERTICAL TIMBER UNDERPINNING

I HIRED A CONTRACTOR TO BUILD MY TIMBER FRAME HOME WITH SIPS SHELL. CONTRACTOR INTENDS TO INSTALL TIMBER FRAME ONTO THE FLOOR SHEETING WITH CUTOFF RIGHT UNDER SUBFLOOR WITHOUT CONTACTING FOUNDATION. HE PLANS ON GENERAL CONTRACTOR INSTALLING SQUISH BLOCKS OR SCRAP LUMBER BETWEEN FOUNDATION PLATE AND UNDERSIDE OF TIMBER AFTER BUILDING IS ERECTED. I DO NOT BELIEVE THIS IS STRUCTURALLY SOUND. PLEASE GIVE ADVISE ON IF THIS IS A COMMON ENGINEERED PRACTICE AND SHOULD I AGREE WITH THIS TYPE OF INSTALL.

Frame should be erected on blocks already there. Not after the fact. After the fact is not common practice in my opinion.

Jim Rogers

Easy on the caplocks.

No, it's not a common or really recommended practice. I'm sure that it can be remedied pretty easily--it's just a few blocks. It could be the job of either trade, it's just a communication issue. It's the GC's job to make that clear beforehand.

I'd say that it's typically within the carpeneter's scope, but it's the TFer's (through the GC) responsibility to give an indication of where they want additional blocking.

I have seen people do this, but I have never been a proponent. I prefer to drop posts into framed pockets in the framing with the post bottom contacting the treated plate.
Without knowing the details of what your contractor is proposing it is hard to say it is wrong, but you are certainly right to be asking questions. Who is doing the engineering on this project? Can you get them involved?

How are the posts going to be tied to the foundation?

Jim

Blocking under the posts is common with hand raisings, where you don't want the bents dropping 10 inches or so as they get vertical. I believe it's acceptable from an engineering standpoint if the blocks have their grain oriented vertically. One block is left shorter than the others to accept a stub tenon on the post. They definitely should go in before the frame goes up; I don't see how it could be done otherwise without the plywood bending or even shearing through. For crane raisings, and in general, having the posts go all the way to the foundation/sill is preferable.