superstruction

noun2

1. •
   (no longer used) That which is built on some foundation; an edifice; a superstructure.

   • […] for I love not to improve the Honour of the Living, by impairing that of the Dead; and my own Profession hath taught me, not to erect new Superstructions upon an old Ruin. — 1668
2. •
   (no longer used) The act of superstructing, or building upon.

   • The wall has been thickened to give dept to the gateway, and possibly to allow of the superstruction of a low tower above it. — 1852