Your problem is that you're attempting to analyse a very poorly constructed sentence! (Are you certain that it was written by a native?)
In the first place 'belittled' would not be used to describe a building: it means 'made to look figuratively (not literally) small'.
In the second, the statement that something is 'X feet tall' is a statement about its absolute height (from its bottom to its top), not its height relative to some other object on the ground. For the latter case, we would say 'stand/tower/... X feet above/over...' without 'tall'.
However, in case it may be of help to you in terms of general analysis, in both
He is six feet tall.
and (somewhat less natural, but still possible)
He stands six feet tall.
the underlined part is an adjective phrase (consisting of head 'tall' modified by adverbial objective 'six feet') serving as a subject-complement.
He slides the box open.
adjective 'open' serves as an object-complement. ('Slides' is, of course, a verb...)