Catasto vs reality: when the floor plans don't match the house.

One of the most under-appreciated risks in buying an older Italian home is the gap between the property on paper and the property in front of you. Italy operates a strict requirement known as doppia conformità, double compliance, and since 2010 the notary is legally required to verify cadastral compliance before completing a sale. Get this wrong and the deed can be blocked, the bank can refuse to lend, and in the worst cases the act can be declared null and void. This is what every foreign buyer needs to understand about the catasto.

Italy's two registries: Catasto and Conservatoria

First, a crucial distinction many buyers miss: Italy keeps two separate record systems. The Catasto (cadastral records) holds the property's technical data and floor plan and serves mainly a fiscal purpose, calculating taxes like IMU. The Conservatoria (land registry) records ownership transfers, mortgages and liens. You need to check both to confirm clear title, because the cadastral record alone is not proof of legal ownership.

Urban compliance vs cadastral compliance

"Double compliance" means two different things must both be true:

• Cadastral compliance (conformità catastale): the registered floor plan (planimetria) must match the property's actual internal and external layout.
• Urban compliance (conformità urbanistica): the building as it stands must match the permits filed with the municipality (Permesso di Costruire, SCIA, CILA and so on).

A property can be compliant in the Catasto but not urbanistically, and vice versa. Both must be verified. And critically, the notary checks cadastral compliance but does not verify urban compliance, which is precisely where foreign buyers most often get caught.

Why mismatches are so common, and when they're a problem

Decades of small undocumented changes, an enclosed balcony, a divided room, an extra bathroom, an added outbuilding, leave many older homes out of step with their records. Some are minor and can be regularised through a simplified procedure or a building amnesty (paying a fine, the oblazione, and updating the plan). But not all irregularities can be legalised, particularly in protected coastal, landscape or archaeological zones, and the cost and time of regularisation can be significant.

What to do before you sign

• Compare the registered planimetria with the property you actually walked through.
• Review the drawings held by the municipality, not only the Catasto.
• Instruct a geometra to certify both cadastral and urban compliance.
• Get written confirmation there are no demolition orders or pending sanctions.

A mismatch is not automatically a deal-breaker, but it is a question that must be answered, in writing, before you sign a binding proposal or pay a deposit. An unresolved discrepancy is one of the few issues that can genuinely void an Italian sale.

The difference between a sanatoria and an unfixable abuso

Not every irregularity is equal. A minor, recent change that complied with the rules in force when it was made can often be regularised through a sanatoria, updating the plan and paying a fine (the oblazione). But works that never could have been authorised, particularly in protected landscape, coastal, seismic or historic zones, may be impossible to legalise, and in serious cases can attract demolition orders. The distinction is technical, which is exactly why a geometra's certification, and a notary's title check, must happen before you are committed.

What to write into your offer

• A condition that the seller delivers full cadastral and urban compliance before completion.
• A right to withdraw with your deposit returned if compliance cannot be achieved.
• Clarity on who bears the cost and time of any sanatoria.

Common mistakes with catasto and compliance

• Assuming the notary checks everything, they verify cadastral but not urban compliance.
• Relying on the cadastral record as proof of ownership; that is the Conservatoria's job.
• Buying before a geometra certifies both urban and cadastral conformity.
• Believing every irregularity can be amnestied, some cannot, especially in protected zones.

Frequently asked questions

What is doppia conformità?

Double compliance: the property must match both its registered cadastral plan and the permits filed with the municipality.

Can a cadastral mismatch void the sale?

Serious discrepancies can block completion or render the deed challengeable, which is why they must be resolved before signing.

Who fixes a mismatch?

A geometra updates the plan or pursues a sanatoria; agree in the contract whether the seller resolves it before completion.

Sources & further reading

• Agenzia delle Entrate — property guides
• Consiglio Nazionale del Notariato