When you buy a flat in Portugal, you buy a fraction defined by a document most buyers never read: the horizontal-property title (título constitutivo da propriedade horizontal). It fixes what your flat is, what share of the building it carries, what it may be used for and which storage room, parking space or terrace comes with it. Changing it needs every owner in the building to agree (Código Civil, Art. 1419.º). Since Decreto-Lei n.º 10/2024 nobody compares the flat with that title before the deed, and works done outside it can expose the owner to fines under the RJUE. Our pre-purchase property inspection guide covers the whole inspection. This guide sets the title beside the flat, row by row, and shows where an InspectOS Pre-Purchase Inspection finds the gaps.
Table of Contents
- What is a horizontal-property title?
- What does the title fix about your flat?
- Where do the flat and the title most often part ways?
- Who has to agree before a mismatch can be put right?
- What does an inspection add to the paperwork?
- Frequently Asked Questions
What is a horizontal-property title?
The horizontal-property title splits a Portuguese building into independent fractions and defines each one, under Articles 1414.º to 1438.º-A of the Código Civil.
Flats in Portugal are owned outright, not on a lease. An apartment building is held in horizontal property (propriedade horizontal): each owner owns their fraction outright and co-owns the common parts of the building, and the two cannot be sold apart (Código Civil, Art. 1420.º).
A fraction can only exist if it is an independent unit, distinct and isolated from the others, with its own exit to a common part or to the street (Art. 1415.º). The title (título constitutivo) is the document that creates the fractions. In most new buildings it is made when construction ends, and it is recorded at the Conservatória do Registo Predial, where each fraction gets its own letter and description.
A foreign buyer meets the result without meeting the document. The listing says "T2 with storage and parking". The certidão permanente says "fração C". The title says what fração C is.
What does the title fix about your flat?
By law the title must individualise every fraction and fix its relative value; it may also state each fraction's use (Código Civil, Art. 1418.º).
Two things are mandatory. The title must specify the parts of the building that make up each fraction, so that each is individualised, and it must fix the relative value of each fraction as a percentage or permilagem of the whole building (Art. 1418.º n.º 1).
Several more are common:
- The use (fim) of each fraction, for example housing, shop or office. If the title states a use, that use has to match the project the câmara approved, or the title is null (Art. 1418.º n.º 3).
- Annexed parts listed as belonging to the fraction: a storage room (arrecadação) in the basement or the attic, a parking space in the garage.
- Exclusive-use areas: parts of the common areas that the title reserves for one owner, such as a roof terrace or a patch of garden (Art. 1421.º n.º 3).
- Building rules (regulamento do condomínio) on use and upkeep.
The permilagem matters beyond the paper. As a rule, it sets your share of the building's common costs (Art. 1424.º) and the weight of your vote in the owners' assembly.
Ask the seller, or the building administrator, for a copy of the title, and read it next to the certidão permanente for the fraction and the caderneta predial from the tax authority.
Where do the flat and the title most often part ways?
Most gaps sit in six places: composition, area, use, annexed spaces, exclusive-use areas and enclosed balconies or attics added after the title.
The table in the asset above sets them side by side. In words:
Composition. The title and the registry describe a T2; the flat on offer is a T3 because a living room was split. Internal changes like this can be lawful, but walls that carried load, or a change in the number of rooms, may have needed licensing. Our guide to the Portuguese habitation licence covers that document.
Area. The flat measures more than the title and the registry record. Registry law tolerates small differences; larger ones are a survey and rectification job before a clean sale. Extra square metres most often turn out to be a closed balcony or an annexed space absorbed into the flat.
Use. A ground-floor fraction titled as a shop is sold as a flat. Since Decreto-Lei n.º 10/2024, changing a fraction's use to housing no longer needs the other owners' consent: the owner communicates the new use to the câmara and can then amend the title alone, by deed or authenticated document (Código Civil, Art. 1422.º-B). If neither step happened, the flat is used against its title (Art. 1422.º n.º 2 c)) and without a municipal title of use.
Annexed spaces. The listing includes a storage room or a parking space that the title does not attach to this fraction. Garages and parking spaces are presumed common unless the title says otherwise (Art. 1421.º n.º 2 d)). Some are separate fractions with their own letter and price.
Exclusive-use areas. A top-floor flat "with private terrace". The roof and roof terraces are common parts even when they serve a single fraction (Art. 1421.º n.º 1 b)). The title can reserve their use to one fraction. If it does not, the terrace is shared.
Enclosed balconies and attic rooms. A marquise (closed balcony), a glazed veranda or an attic turned into a bedroom. Works that change the building's architectural line or appearance need prior approval from owners representing two thirds of the building's value (Art. 1422.º n.º 3), and many also need municipal control. The attic may be a common part, not the seller's.
Our guide to checking for illegal extensions shows how these additions look on a viewing.
Who has to agree before a mismatch can be put right?
Changing a horizontal-property title needs the agreement of every owner in the building, by public deed or authenticated private document (Art. 1419.º).
This is the reason a mismatch matters more in a flat than in a house. A house owner can legalise works alone. A flat owner whose fraction no longer matches its title may need the whole building.
The paths, from easiest to hardest:
- Assembly approval for a façade change. Owners representing two thirds of the building's value can authorise works that alter the architectural line or appearance (Art. 1422.º n.º 3). That approval, recorded in the assembly minutes, is the first document to ask for when a flat has a marquise.
- Joining fractions. Two contiguous fractions can be joined into one without the other owners' consent, and storage rooms and garages need not be contiguous (Art. 1422.º-A n.ºs 1 and 2).
- Changing a fraction's use to housing. No consent from the other owners since DL 10/2024: after the municipal communication, the owner amends the title alone and tells the administrator within 10 days (Art. 1422.º-B).
- Splitting a fraction. Dividing a fraction into new fractions needs authorisation in the title or an assembly vote with no opposition (Art. 1422.º-A n.º 3).
- Changing the title itself for anything else, such as area, annexed parts or a use other than housing: agreement of all owners (Art. 1419.º n.º 1). A court can supply missing agreement only for common parts, only if the objectors hold less than a tenth of the value, and only if the change leaves use, relative value and purpose of the fractions untouched (Art. 1419.º n.º 2).
Municipal licensing runs in parallel. Assembly approval does not replace the câmara's control where the works needed it. Condominium debts and the administrator's declaration at the sale belong to the transaction side and are for your lawyer.
What does an inspection add to the paperwork?
An engineer measures the fraction, counts its rooms and identifies later closures, then sets each finding against the title, the registry and the licence.
Reading the title is a desk job you can do. Knowing whether the flat matches it needs a site visit. An InspectOS Pre-Purchase Inspection, carried out by an engineer registered with the Ordem dos Engenheiros, records:
- the measured area of the fraction and of any storage room or parking space shown as part of it;
- the room layout against the composition in the title and the licence;
- enclosed balconies, glazed verandas, attic rooms and roof-terrace structures, and whether they touch the façade or the structure;
- walls removed or added, with attention to walls that may have been load-bearing;
- which spaces the seller uses that the title shows as common.
In Lisbon, about 20% of buildings predate 1919 (INE, Censos 2021); in those blocks the fractions were drawn on a building that already existed. Our Lisbon apartment inspection guide covers the building side.
The report arrives within 48 hours of the site visit, in time to take a mismatch into the CPCV (promissory purchase contract) negotiation. Set its cost against the RJUE fine exposure for unlicensed works, which passes with the fraction at the deed.
Frequently Asked Questions
What is horizontal property in Portugal?
It is the regime under which a building is divided into independent fractions owned by different people, each of whom also co-owns the common parts. It is set out in Articles 1414.º to 1438.º-A of the Código Civil and created by a title recorded at the land registry.
Where can I get a copy of the horizontal-property title?
Ask the seller or the building administrator first. The certidão permanente from the Conservatória do Registo Predial shows the description of each fraction and the registration of the horizontal property, and your lawyer can obtain the constituting document itself.
Is a roof terrace sold with a top-floor flat private?
The roof and roof terraces are common parts under Art. 1421.º of the Código Civil, even when only one flat reaches them. The title can reserve their use to one fraction. If it does not, the terrace is shared, whatever the listing says.
Can a closed balcony make a flat impossible to sell?
No. The sale can still go ahead, but the buyer takes on the balcony as it is. Without the owners' two-thirds approval and any municipal control it needed, the new owner can be asked to reverse it and faces the RJUE fine exposure.
Conclusion
A Portuguese flat is the fraction its title describes. Read the title next to the registry, then book an InspectOS Pre-Purchase Inspection so that the rooms, the area and every closed balcony are checked against it before you sign the CPCV.
→ Book a Pre-Purchase Inspection · get a quote at inspectos.pt/en/home-inspections
Updated October 2026 | InspectOS Portugal · Legal references last reviewed 26 September 2026
Sources: Código Civil, Articles 1414.º, 1415.º, 1418.º, 1419.º (as amended by Lei n.º 8/2022, in force 10 April 2022), 1420.º, 1421.º, 1422.º, 1422.º-A, 1422.º-B (added by Decreto-Lei n.º 10/2024) and 1424.º · Decreto-Lei n.º 555/99 (RJUE), fine ranges, as amended by Decreto-Lei n.º 10/2024 (in force 1 January 2024) and Decreto-Lei n.º 108/2026 (in force 1 October 2026) · INE, Censos 2021 (Lisbon buildings by construction period)