The subfloor is 3/4" tongue-in-groove Advantech 4x8 plywood. This product is supposed to be able to shed water for 90 days or so--giving builders time to get the roof up before moisture damage can occur. The pictures show Terry and me standing about idly while Jim is down on his knees trying to figure out a problem in making the last few pieces of plywood fit. (Really and truly, Terry and I are not always so idle!)
The next two snapshots show the current state of the project. Look closely and you can see the temporary cleats (or blocks) near the top of the posts. Today's work will have us lifting 2x12 beams to rest on those blocks. We will glue, nail, and bolt them to the posts.
Note the various cross braces in the snapshot below. No matter how hard one tries, it is impossible to get the posts perfectly vertical as they are lifted and cemented into the foundation holes. The bracing brings them into better position and will stay in place until the 4x4 cross beams firm up the entire frame.
One of my biggest nightmares in the planning of this addition has been calculating the exact height at which the beams should attach to each post. The new roof must wedge under the roof on the old part of the cabin with at least ten inches of clearance (to allow hammering, etc.). The ceiling in the lowest part of the new addition should be adequate (about 90" or more). The pass-through from the new addition to the bathroom in the old cabin has about a 5" step up and the must pass right beneath the lowest part of a major beam; head clearance of about 78" is required. Some of these specifications conflict with one another in vexing ways. Indeed, it was almost impossible to find a way to have enough head room in the passthrough to the bath. Eventually I decided to add several sub-posts along the east wall, allowing me to cut the main beam from 2x12 down to 2x6.
The little sketch below was an early attempt to check my calculations of roof slope. It barely hints at the hours of measuring, calculating, and remeasuring that I have done. On one sad day (just before 5 PM--exactly the wrong time to make a major decision) I cut two of the center posts off too short. Initially it appeared that I would have only 1 1/2" of exposed post on which to attach my main support beams! Not good! I spent a whole day cutting big dadoes and biscuits so that I could lengthen those two posts. After much additional calculation I found that the beams would actually attach enough lower on the posts to allow my bolts to run through firm wood, but the extensions are still helpful.