The ceiling of the first floor was kind of confusing.  The plans called for using parallams and 2×12’s to make the floor of the second story.  As I discovered, 2×12 does not mean that the boards are 12 inches wide.  It means that they are anywere from 11 1/4″ to 11 1/2″ wide.  You would think that parallams, being engineered lumber, would actually be the size that they are labeled as.  You would be wrong.  We used several thicknesses of parallams, and they were all supposed to be 12″ wide.  They actually measured out at a consistent 11 7/8″ in width. 

Does any one see the problem? 

If the 2×12’s are attached to the 12″ wide parallams forming a level surface for the top of floor, the bottom of the floor (the ceiling of the first story) is going to be very uneven.  The parallams hung down around 1/2″ below the rest of the ceiling joists.  This does not make for good surface to hang drywall from.

The drywallers ended up butting the drywall up against the beams and then taping / mudding directly on the beams themselves, without any drywall.  You can see the brown beams in the pictures from a previous post.  Here is what the ceilings look like after the extra mud.