We have a wall! We're hoping there will be more, and perhaps a roof at some point, but we'll start with a wall. The excavation/concrete team was out on Monday adding additional rebar to the footer to form what would ultimately become both the retaining wall and the rear wall of the addition. They later put up the "forms" (big metal sheets) into which they could pour the concrete to make said wall.
It was around Tuesday that I noticed that they were putting up forms around both the left and right wall in addition to the rear wall. After some questionting, it turns out that we are going to have some pretty serious portions of our side walls be concrete. I don't really know if that's any better or worse than 2x6's and insulation. If anyone does know, feel free to comment.
Some additional excitement came early Wednesday morning when we awoke to them uprooting a tree in the yard. I won't go into detail, but let's just say that Colleen's mom 'had a bad experience' during the original addition with certain plants being bulldozed so now she's particularly on edge about that sort of thing. Apparently they were not willing to pay the extra $800 for the concrete pump to get the concrete high enough to pour into the forms and so they were going to blaze a trail into the backyard for the truck. Fortunately, Colleen's dad was able to talk with the excavator and they mutually agreed on a path that would spare one of the more favorite trees. Crisis averted.
Once that was all figured out, they poured the concrete and all was well. Our new wall is currently drying out (it's such a wonderful, quiet activity at 7am). Rumor has it we'll have a floor on Monday or Tuesday.