Originally it had four rooms, each with independent entrance.  The Mayan vault that is preserved was made with long slabs placed in a projecting way, but showing its edges, in a way that reminds us of a staircase seen from the top. This technique corresponds to the transition between the Petén works and the beginning of Puuc architecture. Therefore, the construction is dated between the years 600 to 650 of our era (Proto-Puuc phase).

Detail of the Inverted Staircase Vault Building: Cut of one of the four rooms that allows us to understand why this building is called “with inverted staircase vault”.