Splitting the costs of a flat roof terrace

When Article 1126 of the Civil Code applies

Article 1126 of the Italian Civil Code applies when a flat roof terrace, or a level terrace serving the same covering function, is not shared by all owners but is used exclusively by one or a few of them, for example because it is accessed only from a specific apartment and used as a private terrace. This differs from a shared roof, whose maintenance falls on the whole building according to the general ownership shares.

The rule states that whoever has exclusive use of the roof must contribute one third of the repair or reconstruction costs, while the remaining two thirds fall on all the owners the roof serves as a cover, in proportion to the value of each one's floor or portion of floor. The reasoning is straightforward: whoever uses the roof exclusively gains an extra benefit compared to the others, so they contribute more, but the roof's covering function remains a collective benefit, hence the larger share carried by everyone.

The one third and two thirds rule: how it is calculated

In practice the calculation works as follows: the total cost of the works is split into two shares, one third and two thirds. The one third share is charged entirely to the owner with exclusive use of the roof, regardless of their general ownership share. The remaining two thirds are split among all the owners who receive the covering function from the roof, according to the ownership shares tied to their respective units, not the building's general shares if these differ.

It is important to distinguish this case from a roof shared by all, where there is no one third allocation at all: in that case the expense simply follows the general ownership shares. Before any works, a property manager must therefore verify whether the roof has a documented exclusive use (bylaws, deeds, established practice) or whether it is genuinely shared, because the difference entirely changes the allocation.

• One third of the cost: charged to the owner with exclusive use
• Two thirds of the cost: charged to the owners below, based on the shares of their respective units
• Preliminary check: confirm whether the use is truly exclusive before applying the rule

Water infiltration and liability for neglected maintenance

A recurring issue involves infiltration damage from the roof affecting the apartments below. Case law distinguishes between the allocation of ordinary maintenance costs, which still follows the rule under Article 1126, and liability for infiltration damage, which can also fall on the custodian of the asset under Article 2051 of the Civil Code if a maintenance defect attributable to whoever has exclusive availability of it is proven.

The correct practice for a property manager is to keep the two matters separate: on one side the allocation of ordinary and extraordinary maintenance costs on the roof under Article 1126, on the other any assessment of liability for damage already occurred, which follows general civil liability rules and may require a dedicated insurance policy or a separate claim against the party responsible.

Accounting management in the financial statement

In the financial statement, the cost of works on an exclusively used flat roof terrace should be shown in a dedicated allocation table, kept separate from the building's general expenses table, because the parties liable for payment and the allocation criteria differ. The one third share is charged specifically to the owner with exclusive use, while the two thirds are split among the others according to the relevant table.

Managing this with dedicated software, such as AmministraPro, allows configuring specific allocation tables for this type of expense, automating the calculation of the one third and remaining two thirds shares without recalculating manually at every intervention, reducing the risk of errors and making the financial statement clearer at the assembly meeting.

Frequently asked questions