Splitting a property in Italy: permits, fees, room standards, cadastre and habitability

Splitting a property in Italy means turning one dwelling into two or more independent units: a villa divided into two homes for two generations of a family, a house with a separate flat on the ground floor, a large apartment made into two smaller ones. The reverse operation, merging two units into one, is called accorpamento. In both cases moving a few walls is not enough: the building permit route, the services, the cadastral records, the relationship with any condominium and, at the end, the certificate of habitability all change.

This guide explains how splitting a property works in Italy for a house or a villa: how the Consolidated Building Act (Testo unico dell’edilizia, Presidential Decree 380/2001) classifies it, which application is needed, what happens to planning load and fees, which room standards the new units must meet, how services and utility connections are separated, how the cadastre is updated and the most frequent mistakes.

It is written by Federico Cappellina Architects, an architecture practice in Verona that designs houses in north-east Italy and Lombardy and supervises their construction, for foreign owners and buyers. It is not legal advice or a binding technical opinion: regional and municipal rules vary and must be checked with the municipality.

Splitting a property in brief

Splitting a property into units, and merging units, fall within the maintenance category of Article 3, paragraph 1, letter b) of Presidential Decree 380/2001, even when the floor areas of the single units and the planning load change, provided the overall volume does not change and the original use is kept.
Without structural works and without changes to the façades the application is normally a CILA, a certified notice of works (Article 6-bis); with structures or façades it becomes a SCIA, a certified notice of start of works (Article 22); the building permit returns in the cases of Article 10.
When planning load increases, fees may be due: Article 17 links the contribution, for this kind of maintenance, to the infrastructure share and to an increase in walkable floor area.
Every new unit must meet the national health and room standards and the minimums of the municipal building regulation, which differ between municipalities.
The cadastre is updated with a Docfa filing, normally prepared by a licensed professional, within thirty days of the end of the change.
After the works a certified notice of habitability is filed within fifteen days of completing the finishes, when the works affect safety, hygiene, healthiness or energy saving.

Splitting a property and a single-storey villa: CD Home in Verona, glazed façade at dusk, a project by the studio — CD Home, Verona: a project by the studio shown as a reference of language, not as an example of splitting a property.

What splitting a property means in Italy

In Italian building law, splitting a property (frazionamento) concerns property units (unità immobiliari), not land. It is the division of one unit, with its own entrances, bathrooms and services, into several units, each able to function on its own. It should not be confused with the cadastral subdivision of a plot of land, which splits a land parcel, or with the division of an estate between heirs, which is a legal act and may leave the building as it is.

A well-executed split produces units that can be sold, let or lived in separately without depending on each other: an entrance of their own, or a shared one with clear rules, a kitchen and a bathroom for each unit, separate services and meters, and a cadastral floor plan for each. If one unit is still served by the other’s systems, or can be reached only by walking through it, the division is incomplete, and the problems appear at the first sale.

Merging follows the same route in reverse: two adjoining units become one. Here too a building application, a cadastral update and a check of the services are needed, and in a condominium the sharing of costs changes.

Splitting a property under Article 3 of Presidential Decree 380/2001

We read Article 3 of Presidential Decree 380/2001 in the current text on Normattiva, the official Italian legislation database. Paragraph 1, letter b) defines a category of maintenance covering the renewal and replacement of parts of buildings, including structural parts, and the creation or upgrading of bathrooms and technical services, provided the overall volume of the building is not altered and there is no change of use, relevant for planning, that increases the planning load.

The same letter b) expressly includes the splitting or merging of property units, even when the floor areas of the single units and the planning load change, provided the overall volume of the building is not modified and the original use is kept. For splitting a property there are therefore two conditions to check:

overall volume unchanged: if enclosing a portico, raising a floor or building an extension is needed to create the second unit, the works are no longer just a split;
original use kept: a house divided into two homes stays residential; turning part of it into an office or a shop raises the question of a change of use.

The reference to an allowed increase in planning load (carico urbanistico, the demand a building puts on roads, networks, parking and services) matters: two households instead of one bring more cars, more water and more waste. The law accepts this within this maintenance category, but takes it into account for fees, as explained below.

Which permit route applies when splitting a property

The route depends on the works, not on the name of the intervention. In our practice we choose it after the survey and after drawing the final units, because only then do we know whether structures or façades are affected. Our guide on CILA and SCIA renovation permits goes into detail; here is what we read for splitting a property.

CILA: no structural works and no façade changes

Article 6-bis allows works not falling under Articles 6, 10 and 22 to be carried out after a certified notice of works (CILA, comunicazione di inizio lavori asseverata). A licensed professional certifies compliance with planning instruments and building regulations, compatibility with seismic and energy rules and that the works do not affect structural parts; the notice also identifies the contractor.

A split made with new partition walls, a second bathroom, a kitchen and separate services, without touching structures and façades, normally falls here. Failing to file the certified notice carries a penalty of 1,000 euros, reduced by two thirds if the notice is filed spontaneously while the works are under way. Ordinary-statute Regions may extend this procedure to further works, which is another reason to check the regional rule and the municipality.

SCIA: structures or façades

Article 22, paragraph 1, letter a) requires a certified notice of start of works (SCIA, segnalazione certificata di inizio attività) for letter b) maintenance when it affects the structural parts of the building or its façades. When dividing a villa this happens often: a new front door in the façade, a window enlarged to light a kitchen, a load-bearing wall cut to create a hallway, an external staircase. Each of these moves the application from CILA to SCIA.

Building permit: when the intervention changes nature

Article 10, paragraph 1, letter c) requires a building permit (permesso di costruire) for renovation that produces a building wholly or partly different from the previous one, when it changes the overall volume or, in historic zones A, the use, and for works that change the outline, overall volume or façades of properties protected under the Cultural Heritage and Landscape Code.

The current text we read does not mention the number of units, but a split combined with an extension in practice falls within these cases. See our guide to the building permit in Italy.

Planning load and fees when splitting a property

Dividing a house into two units normally increases its planning load. Article 17, paragraph 4 provides that for maintenance works that increase the planning load the building contribution is limited to the share of infrastructure charges (oneri di urbanizzazione), provided the works increase the walkable floor area. The paragraph refers to maintenance under Article 6, paragraph 2, letter a), an older numbering, so how it applies to a split should be confirmed with the municipality.

Paragraph 4-bis of the same article reduces the contribution by no less than 20% compared with the regional tables for urban regeneration, recovery and reuse, and allows municipalities to decide further reductions, up to exemption. Amounts, parameters and how the municipality measures the increase in floor area are set by municipal resolutions. In our practice we ask the technical office, before filing, whether and how it applies fees to the specific split, and we keep the answer in the project file.

Planning load also has practical effects: some municipal regulations require parking spaces for each new unit or a minimum floor area per dwelling. These are local rules, found in the building regulation and in the technical rules of the plan.

Health and room standards for the new units

Each unit created by a split is a dwelling in its own right and must meet the standards for living spaces. The national reference is the Ministry of Health decree of 5 July 1975, which we read in a copy of the text of the decree of 5 July 1975 (Normattiva would not load it). According to that text:

the minimum internal height of habitable rooms is 2.70 m, reducible to 2.40 m for corridors, hallways, bathrooms, toilets and storerooms (2.55 m for habitable rooms in mountain municipalities above 1,000 m);
habitable floor area is at least 14 m² for each of the first four occupants and 10 m² for each further occupant;
bedrooms measure at least 9 m² for one person and 14 m² for two; each dwelling has a living room of at least 14 m²;
a studio flat, bathroom included, measures at least 28 m² for one person and 38 m² for two;
the openable window area is at least 1/8 of the floor area, with an average daylight factor of no less than 2%;
the bathroom has an opening to the outside or mechanical extraction.

The derogations in Article 24

Paragraphs 5-bis and 5-ter of Article 24, in the text in force since 28 July 2024, allow the designer, pending the new standards provided by Article 20, paragraph 1-bis, to certify health compliance with internal heights below 2.70 m down to 2.40 m and with studio flats down to 20 m² for one person and 28 m² for two.

The adaptability requirement of Ministerial Decree 236/1989 must be met, plus at least one condition: rooms in buildings undergoing recovery and health improvement, or a design with alternative solutions (more floor area or adequate natural ventilation).

Municipal minimums

Many municipal building regulations set minimum floor areas for new units, ratios between small and large units, and parking or cellar requirements. They vary between municipalities and change over time: a split may be allowed in one municipality and not in the next one with the same house. They must be read in the version in force before the units are drawn.

Splitting a property and house design: AV Home in Dueville, stacked white volumes and pool at dusk, a project by the studio — AV Home, Dueville (Vicenza): a project by the studio shown as a reference of language, not as an example of the topic of this page.

Separate services and utility connections

The most expensive part of a split is often invisible: the services. In our practice two independent units need separate electricity meters, their own gas supply or heat source, a water meter each, drains that do not run through the other unit where this can be avoided, and a data line for each dwelling.

Electricity: a consumer unit and meter for each dwelling, with shared lines (outdoor lights, gate, pumps) separated and assigned.
Heating and cooling: independent generators or a central system with individual metering; the choice affects running costs, maintenance and the energy performance certificate of each unit.
Water and drainage: connections and meters from the utility company, on timescales outside the architect’s control, which are worth starting early.
Sound and fire: the wall or floor between two units becomes a boundary between properties; in our practice we design it as such, checking the rules that apply to the case.

At the end of the works the installer issues a declaration of conformity of the systems, which Article 24, paragraph 5, letter e) lists among the habitability documents. Without complete declarations for each unit, the file cannot be closed.

The cadastre: the Docfa filing

After the split, the cadastre (catasto, the property register used for taxation) must show the new units. The Italian Revenue Agency page on Docfa, which we read, explains that Docfa is the procedure for filing the update of the Buildings Cadastre for new buildings and for changes to registered units that require a review of category, class or size. Since 1 June 2015 filing is online only.

The obligation lies with the holders of property rights; the filing is normally prepared by a licensed technical professional and sent through the Agency’s Sister platform.
The deadline is thirty days; for units already registered it runs from the end of the change. Late filing carries the penalties provided by law.
For CILA works, Article 6-bis, paragraph 3, provides that, if the end-of-works notice is accompanied by the cadastral documents, the municipality forwards them to the Revenue Agency.

In our practice the cadastral plans of the new units are drawn together with the building design, with the same measurements: a gap between design, cadastre and as-built state is one of the topics of our guide on the planning compliance check. The new units receive their own identifiers, and shared parts such as an entrance or a common courtyard are shown separately.

Splitting a property in a condominium

If the house is already part of a condominium, or if the split creates one, the condominium rules, the common parts and the sharing of costs come into play. We did not read the Civil Code articles on condominiums at source and do not quote them; we list only the points that, in our practice, are checked before the design.

The condominium regulation, especially one written into the deeds, may limit the division of units or the use of common parts.
The thousandths tables (tabelle millesimali) that share costs must assign values to the new units; the revision must be agreed and documented.
New service routes on the façade, in the stairwell or on the roof affect common parts.
When dividing a family villa, it is worth settling at once, with the notary, which spaces stay shared (garden, access, plant room) and how costs are divided.

The certificate of habitability after splitting a property

Article 24 states that habitability (agibilità: safety, hygiene, healthiness, energy saving and conformity with the design) is certified by a notice. It is filed within fifteen days of completing the finishes, also for works on existing buildings that may affect those conditions: splitting a property with new bathrooms, kitchens and services normally falls here. Failing to file carries a penalty of 77 to 464 euros.

The notice may also cover single units, if the related structural works are completed and tested, the services certified and the common parts and infrastructure serving the building completed. It is accompanied, among other things, by a statement of the site supervisor or a licensed professional, the reference of the cadastral update and the installers’ declarations of conformity. Our guide to the certificate of habitability in Italy lists the documents.

Merging units: the same route in reverse

Merging two units is in the same letter b) of Article 3 and follows the same rules on the permit route: CILA without structures and façades, SCIA if an opening is cut in a load-bearing wall or a façade is changed. Services are unified, surplus meters are closed and the cadastre is updated with a new filing.

In our practice, before merging, we check that both units are lawful: joining a compliant unit to one with irregularities carries the irregularity into the new unit, and the application brings it to light. See also our guide on regularising building works in Italy.

Our method for splitting a property such as a villa

In our practice a split follows these steps, in the same order as the house design process in Italy:

Lawful state: building permits, cadastral plans, any construction tolerances.
Survey of the building, its structures and its existing services.
Municipal rules: minimum floor areas, parking, fees, constraints such as the hydrogeological constraint.
Design of the units, with entrances, daylight, services and the boundaries between properties.
Choice of route (CILA, SCIA or permit) on the basis of the actual works.
Construction drawings and costing: the construction drawings and the bill of quantities separate the costs of each unit.
Site with a construction schedule, site supervision and the handling of any design changes during construction.
Close-out: end of works, Docfa, installers’ declarations, energy certificates, habitability.

Splitting a property and the building site: AV Home in Dueville seen from the road with the cantilevered volume under construction, a project by the studio — AV Home, Dueville (Vicenza): the building site of a project by the studio, shown as a reference of language, not as an example of the topic of this page.

Frequent mistakes when splitting a property

Starting from the walls, not the rules: drawing two units and then finding that the municipality requires a minimum floor area or an extra parking space.
Choosing a CILA without checking the works: a new door in the façade or an opening in a load-bearing wall requires a SCIA.
Adding volume by enclosing a portico or a loggia to create the second unit: the works leave letter b).
Changing the use of part of the house without treating it as a change of use.
Leaving shared services unregulated: one boiler for two units without metering causes disputes and problems at sale.
Forgetting the Docfa filing, or filing it with measurements that differ from the design.
Not filing for habitability and discovering it at the notary’s deed of sale.
Ignoring the condominium and its thousandths tables.
Splitting a property that is not lawful: existing irregularities pass to the new units.

Italian terms at a glance

Frazionamento / accorpamento: splitting a property unit into several, and merging units into one.
Unità immobiliare: a property unit, the dwelling or premises recorded as one item in the cadastre.
Carico urbanistico: planning load, the demand a building places on roads, networks and services.
CILA / SCIA: certified notice of works and certified notice of start of works, the two lighter permit routes.
Permesso di costruire: the building permit, needed for the heavier interventions.
Oneri di urbanizzazione: infrastructure charges, part of the building contribution paid to the municipality.
Docfa: the online procedure for updating the Buildings Cadastre.
Agibilità: habitability, certified by a notice filed after the works.

Frequently asked questions about splitting a property

Is splitting a property in Italy maintenance or renovation?

Article 3, paragraph 1, letter b) of Presidential Decree 380/2001 includes the splitting and merging of property units in the maintenance category of that letter, even when the floor areas of the units and the planning load change, provided the overall volume does not change and the original use is kept. If these conditions are not met, the works must be classified differently.

Does splitting a property need a CILA or a SCIA?

A CILA (Article 6-bis) when neither structural parts nor façades are affected; a SCIA (Article 22, paragraph 1, letter a) when the works affect structures or façades. A building permit returns in the cases of Article 10, for example with changes to the overall volume. Regions may extend the CILA to other works.

Are fees due when splitting a property?

Article 17, paragraph 4, limits the contribution to the infrastructure share for maintenance works that increase the planning load, provided they increase the walkable floor area. Amounts and application depend on municipal resolutions, and the municipality should be asked to confirm.

What is the minimum size of a unit after splitting a property?

The decree of 5 July 1975 sets at least 28 m² for a studio flat for one person and 38 m² for two, bathroom included; Article 24, paragraphs 5-bis and 5-ter, allows minimums of 20 and 28 m² under certain conditions. Many municipal regulations set higher minimums, to be checked.

Who updates the cadastre after splitting a property?

The obligation lies with the holders of property rights; the Docfa filing is normally prepared by a licensed professional and sent online within thirty days of the end of the change, according to the Revenue Agency page.

Is a new certificate of habitability needed after splitting a property?

If the works affect safety, hygiene, healthiness or energy saving, Article 24 requires the certified notice within fifteen days of completing the finishes; it may also cover single units under the conditions of paragraph 4.

Can a villa with a single garden be split?

Yes, if the units are independent and the municipal rules allow it. The garden can be divided or stay shared: the choice should be made before the design and written into the deeds, together with the sharing of costs.

Checks on splitting a property before you start

Splitting a property starts from its lawful state: permits, plans and irregularities are cleared up before drawing.
The overall volume and the original use stay unchanged, otherwise the works leave letter b).
Each unit meets the minimums of the 1975 decree and the often higher ones of the municipal building regulation.
The route is chosen on the actual works: CILA, SCIA or building permit.
There is a written answer from the municipality on fees, parking and minimum areas.
Services, meters and drains are separate for each unit, or governed by written rules where shared.
In a condominium the design goes through its regulation and thousandths tables.
Splitting a property is closed with Docfa, installers’ declarations, energy certificates and the habitability notice.

Splitting a property: operating summary

Splitting a property is decided in this order: the lawful state of the building first, then how the work is classified, then the title, the utilities and the land registry. Splitting a property remains maintenance only if the overall volume and the original use do not change.

Splitting a property and the title: CILA, SCIA or building permit depending on structure, façades and volume.
Splitting a property and room standards: heights, floor areas and ventilation of each new unit, with the 1975 ministerial decree and the municipal building regulation.
Splitting a property and utilities: the installer’s declaration of conformity at the end of the works (Article 24, paragraph 5, letter e).
Splitting a property and the land registry: the Docfa declaration within thirty days of the end of the variation.
Splitting a property and habitability: the notice within fifteen days of finishing the works, when the intervention affects the requirements of Article 24.
Splitting a property is the same path in reverse when two units are merged.

In short, splitting a property is a sequence of controls, and every step of splitting a property should leave a document in the file.