  We define stacky building data for stacky covers in the spirit of Pardini and
give an equivalence of (2,1)-categories between the category of stacky covers
and the category of stacky building data. We show that every stacky cover is a
flat root stack in the sense of Olsson and Borne--Vistoli and give an intrinsic
description of it as a root stack using stacky building data. When the base
scheme S is defined over a field, we give a criterion for when a birational
building datum comes from a tamely ramified cover for a finite abelian group
scheme, generalizing a result of Biswas--Borne.
