Necessarily, there is a deed of New Construction and Horizontal Division, registered in the Land Registry, which establishes the different departments that make up the building and the particular rules that govern the community of owners, which are compulsory for all owners.
All the co-owners have the obligation to contribute to the general expenses of the building and to the maintenance and repair of the installations of which they make use (art. 9 LPH), although I insist that it is necessary to verify the content of the New Building and Horizontal Division in order to verify which specific obligations correspond to each one.