Dividing Wall Between Apartments: Ownership and Costs

The wall separating two adjacent apartments does not belong to the condominium in its entirety, but to the two owners who border it. The presumption of joint ownership under Article 880 of the Italian Civil Code applies: the dividing wall between two properties is presumed common, unless there is contrary proof from a deed or from unequivocal signs of exclusive ownership. The maintenance costs of that wall are therefore not spread across all owners through the general thousandths (millesimi), but split in half between the two neighbours who share it, in proportion to each one's right.

Dividing wall and perimeter wall: two different things

A precise distinction is needed. The perimeter wall that encloses the building and forms its shell is a common part under Article 1117 of the Italian Civil Code, and its costs fall on all owners. The internal dividing wall between two adjacent apartments, on the other hand, does not serve the whole building: it separates two private properties and concerns only the two owners. Confusing the two cases leads to wrong allocations, with improper charges to owners who have nothing to do with that wall.

The presumption of joint ownership under Article 880

The wall that serves as a division between buildings or between real estate units is presumed common up to the height at which one of the two owners builds higher. The presumption can be overcome only by proving, with a title of ownership or with contrary signs, that the wall belongs exclusively to one of the two. In the absence of proof, the wall is common and its preservation is a shared burden between the two neighbours, half each.

• The dividing wall between two apartments is presumed common to the two neighbouring owners.
• Joint ownership concerns only the two neighbours, not the entire condominium.
• Maintenance and rebuilding costs are split in equal parts, unless a different title provides otherwise.
• The presumption falls only with a deed or with contrary signs of exclusive ownership.

What the owner may do on the common wall

Each co-owner may make use of the common dividing wall within the limits of Article 1102 of the Italian Civil Code: they may rest works against it, insert beams, carve niches, provided they do not alter its use, do not compromise its stability and do not prevent the other co-owner from making equal use of it. They may not, however, demolish it, move it or change its function without the neighbour's consent, because that would affect an asset belonging to both. Works that weaken the structure or reduce the other's right are unlawful.

How maintenance costs are shared

Since it is an asset common to only the two neighbours, the costs of preserving and repairing the dividing wall are shared 50% between them, regardless of the general thousandths of each apartment. If the wall must be reinforced, waterproofed or rebuilt because of wear, each of the two pays half. If instead the deterioration results from a negligent action by one of them, for example a break caused by clumsy works, the cost falls entirely on the party who caused the damage, following the general principle of liability.

When the wall is a common part of the building

There is an exception to assess case by case: if the dividing wall also has a load-bearing function for the structure of the whole building, for example it is a master wall onto which the common slabs discharge, its nature may become that of a condominium asset under Article 1117. In that case the costs return to being shared among all owners through the thousandths, because the wall no longer serves only the two apartments but the stability of the building. The classification depends on the wall's actual function, which must be established technically.

The manager's task

Faced with work on a wall between two units, the condominium manager must first classify the asset: dividing wall common to the two neighbours, perimeter wall common to all, or load-bearing wall of structural significance. Only then can they set the correct allocation, avoiding charging all owners a cost that belongs to only two, or vice versa. A documented classification, perhaps supported by a technical report, prevents disputes and challenges to the allocation resolution.

To manage these particular allocations without error, which fall outside the ordinary thousandths, management software that lets you create cost tables dedicated to small groups of units is useful. With AmministraPro you can set up customised allocation criteria even for just two neighbouring apartments, with automatic calculation and traceability: the features are illustrated on the /funzioni page and the plans on the /prezzi page.