Handling a change of use of a unit

What counts as a change of use

A change of use means transforming the function a unit serves compared to its original one: from residential to commercial, from a dwelling to office space, from storage to a unit hosting a hospitality activity. It does not necessarily involve construction works: often a de facto change in how the unit is used is enough, and it produces legal effects both toward the municipality, for planning and cadastral purposes, and toward the condominium.

Article 1122 of the Italian Civil Code establishes that an owner cannot carry out works that damage common parts or harm the stability, safety or architectural appearance of the building, and must give the manager prior notice of works planned on exclusively owned parts if those works can affect common parts. A change of use, even without construction, can therefore trigger a duty to inform when it affects shared systems, increases foot traffic through common entrances, or changes the load on shared drainage.

Effects on the millesimal value tables

Under Article 68 of the implementing provisions of the Civil Code, the value tables are set according to the proportional value of each unit relative to the whole building. Article 69 of the same provisions allows these proportional values to be revised, even in the interest of a single owner, when a change in the condition of part of the building has altered the proportional value of a unit by more than one fifth, including as a result of a change in how the unit is used.

In practice, an office generally has a different market value than a dwelling of the same size, and it is the manager's task to check, with the help of a surveyor, whether the gap exceeds the one fifth threshold: only then does the duty to revise the tables arise, which the assembly can approve by simple majority when the interested parties request it or the appointed surveyor proposes it during an update.

If the change of use also means more intensive use of shared services, such as the lift or centralized heating, it is also worth reviewing the specific usage tables under Article 1123 of the Civil Code, which allocate expenses based on actual use when this diverges significantly from the millesimal value.

The by-laws and restrictions on use

A contractual set of by-laws, meaning one approved unanimously or accepted by reference in the purchase deed, may contain clauses prohibiting certain uses: noisy, nuisance-causing or unhealthy activities, or specifically banned uses such as medical practices, commercial activities or hospitality facilities. If clearly and specifically worded, these clauses bind all owners, present and future, even those unaware of the restriction at the time of purchase, provided the restriction is registered in the property records or otherwise referenced in the deed.

By contrast, by-laws adopted by assembly majority and amendable by majority cannot restrict exclusive ownership rights by imposing use restrictions: they can only govern the use of common parts. It is therefore essential for the manager to check the nature of the existing by-laws before flagging an alleged prohibition to an owner, distinguishing genuinely enforceable restrictions from those with no legal effect.

• Check whether the by-laws are contractual or assembly-adopted
• Verify that the restriction is registered in the property records
• Distinguish use restrictions from architectural appearance limits
• Report disputes between owners to the assembly when they arise

Required communications and the manager's role

An owner planning to change the use of their unit should notify the manager in advance, especially if the change involves works on common parts, increased load on shared systems, or opening premises to the public. Once notified, the manager assesses whether the matter should be brought to the assembly, whether a technical opinion on the value tables is needed, and whether the owners register required under Article 1130 number 6 of the Civil Code, which must record owners' details and the condition of use of each unit, needs updating.

Managing this process digitally reduces the risk of later disputes: keeping the owner's notice, the minutes of any assembly resolution, and the updated registry entry in a single file makes it possible to demonstrate the process was handled correctly if a dispute arises. With AmministraPro the manager can update the owners register, attach documentation of the change of use, and track the communications sent to owners in an orderly way, with the history available for consultation at any time.

Updating the owners register

Once the change of use is finalized, the manager must update the owners register with the new condition of use of the unit, along with cadastral data if this was modified following building works. This update is not a formality for its own sake: it directly affects expense calculations when allocation accounts for actual use, and it serves as a reference in case of transfer of the unit or a new owner taking over, who has the right to know the use officially recognized within the condominium.

Frequently asked questions