Roof of the semi-detached house to be renovated, how are the payments divided if an apartment has been extended?

The building in which there are several distinctly stacked real estate units that each belong to different owners, is considered a condominium by law. Therefore, the rules relating to the condominium also apply when it comes to only two owners, as charito several times by the cassation, most recently with the sentence 15705/2020. Consequently, for the division of expenses, art.