Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sŭpĕr-instrŭo, no perf., ctum, 3, v. a., to build over or upon; to arrange over one another: ut concameratis superinstruas, Cod. Just. 8, 10, 1: ordines vasorum in altitudinem, Col. 9, 7, 3.