Article 1127, last paragraph of the Italian Civil Code provides that Whosoever builds on the top floor must pay the other members of the condominium block of flats in question an indemnity amounting to the current value of the area to be occupied, after having divided by the number of floors (including those to be built) and after having deducted the amount due to the member who is raising a building on the top floor.
A consolidated principle of case law is that the indemnity is paid on the basis of the area used by the building on the top floor – that is to say the vertical projection of the condominium block of flats (cfr. Italian Supreme Court judgment nos. 1055/1967; 959/1961; 1635/1960; 9032/1987) when such building still has to be done (cfr. Italian Supreme Court judgment nos. 1635/1960; 959/1961; 725/1965; 630/1972) and when the building is completed (cfr. Italian Supreme Court judgment nos. 3453/1962; 1300/1977) – without reference to the age of the roof covering the condominium block of flats (cfr. Italian Supreme Court judgment nos. 9032/1987, according to which such data and parameters have nothing to do with the criterion fixed by the legislator for the quantification of the indemnity on the basis of the value of the ground occupied by the condominium block of flats).
The value of such area is calculated on the basis of the value of the neighboring areas and other elements such as the accessibility and location of the area in question (cfr. Italian Supreme Court judgment no. May 18, 1967).
The aforementioned body of case law has recently been upheld by Italian Supreme Court judgment no. 12292 of 2003, which has held that the indemnity provided for under article 1127 is based upon the value of the area on which the condominium block of flats or a part thereof have been raised. This value is determined by dividing the number of floors – including the new floor or floors – and by decreasing the portion due to the member of the condominium who has had the new floor or building done on his or her behalf (such portion being calculated with reference to the floor or part of the floor or floors owned by the latter before such new floor or building was completed) and then sharing the remaining amount among the owners of the other pre-existing apartments (such amount should not, instead, be shared among all the members of the condominium; cfr. also Court of Bologna dated April 13, 2011).