Thanks, Ron, i am looking at the same thing. I had searched under various terms i thought described it, but "gypsum roof deck" opened the whole thing up. I got the folowing link to an old handbook from one of several previous threads on this site that addressed these decks...
I'm trying to determine load capacity for the roof of an indutrial builing that's sheathed with 2" thick gypsum board (no metal or wood decking - just this 2" + 1/2" gyp board ceiling on steel joists). It does not appear to be of the Densdeck or Securerock variety - there's no visible...