The Collaborative International Dictionary of English v.0.48:

Superstruct \Su`per*struct"\, v. t. [L. superstructus, p. p. of
   superstruere to build upon; super over + struere to build.
   See Super-, and Structure.]
   To build over or upon another structure; to erect upon a
   foundation.
   [1913 Webster]

         This is the only proper basis on which to superstruct
         first innocency and then virtue.         --Dr. H. More.
   [1913 Webster]