Practical guide
How to split an expense that serves only some owners
Not every condominium expense is split among everyone. Article 1123, paragraph 3, of the Italian Civil Code establishes that when a building has several stairways, courtyards, flat roofs, works or systems intended to serve only part of the building, the related expenses fall on the group of owners who benefit from them. A system or structure serving a single stairway, a single block or a few units must therefore be funded only by the interested parties, with thousandths (millesimi) calculated within that group. Understanding when this rule applies avoids charging everyone for an expense owed by a few.
What Article 1123 paragraph 3 says
Article 1123 splits expenses into three levels. The first paragraph sets the general rule of allocation by ownership thousandths. The second paragraph introduces the criterion of differing use. The third paragraph governs the case where a building has several parts intended to serve owners differently: the maintenance and management costs of those parts fall on the group of owners who gain an advantage.
The rule reflects a principle of correlation between benefit and contribution. If a common part does not serve the whole building, it is not fair for everyone to pay. The benefiting group forms a kind of partial condominium limited to that expense, without creating a separate autonomous body.
Concrete examples of partial-service expenses
The range of cases is broad and mainly concerns buildings with several blocks or several entrances. These are expenses that remain unrelated to the owners who are not served.
- Maintenance of stairway A charged only to the owners served by that stairway.
- A lift serving only one portion of the building.
- A courtyard or driveway useful only to some units.
- A flat roof covering only part of the building.
- A heating system serving a single block.
- A booster pump feeding only some floors.
How the group's thousandths are calculated
Once the group of interested owners is identified, the expense is split among them. The ordinary criterion remains that of thousandths, but applied only to the units that benefit: you take the thousandth values of those units and rescale them to one thousand within the group, or you use a dedicated table if one exists. For stairs and lifts, Article 1124 also applies, splitting the expense half by ownership thousandths and half by floor height.
When the condominium regulation provides specific tables per stairway, per block or per group of units, the condominium manager must follow them. Absent a dedicated table, the group's perimeter must be reconstructed by looking at the objective benefit of the common part, not at individual preferences.
Common mistakes to avoid
The most common mistake is to split across the whole condominium an expense that serves only some, inflating the shares of those who do not use that common part. The opposite risk is excluding owners who do benefit, for example owners of garages connected to a secondary stairway.
Remember that common ownership does not always coincide with benefit. A part may be common to all under Article 1117 but in practice serve only a group: in that case the benefit criterion of the third paragraph prevails. Documenting the group's boundaries in the minutes and in the allocation reduces disputes.
Managing partial allocation in an orderly way
Applying the third paragraph correctly requires keeping separate tables and linking each expense to the right group. Doing this by hand in complex buildings is laborious and prone to calculation errors.
Software such as AmministraPro lets you define thousandth tables per stairway, block or group of units and link each expense to the correct table, generating allocations that involve only the interested owners. The features are described on the /funzioni page and the plans on the /prezzi page.
Frequently asked questions
When is an expense split only among some owners?
When it concerns common parts, works or systems intended to serve only part of the building, under Article 1123, paragraph 3, of the Italian Civil Code. In that case the expense falls on the group of owners who benefit, not on the whole building.
How are thousandths calculated within the group?
You take the thousandth values of the served units only and rescale them to one thousand within the group, or use a dedicated table from the regulation. For stairs and lifts Article 1124 applies, with half by thousandths and half by floor height.
Who decides which owners belong to the group?
The criterion is objective and looks at the concrete benefit of the common part, not at individual preferences. The condominium manager defines the group by who gains from the work or system; in case of doubt it is advisable to document the choice in the minutes and in the allocation.
Can a part common to all be charged to only some?
Yes. Common ownership under Article 1117 does not always coincide with benefit. If a part in practice serves only a group, the expense follows the benefit criterion of the third paragraph of Article 1123 and falls only on the owners who benefit.
Does software help manage partial allocations?
Yes. Software that lets you create tables per stairway or group and link each expense to the right table reduces errors. AmministraPro generates allocations involving only the interested owners: the features are on /funzioni and the plans on /prezzi.
Try AmministraPro
Accounting, thousandths-based cost splitting, meetings, communications and artificial intelligence in a single Italian software, compliant with UNI 10801 and GDPR.