Useful tipsArchitecture

Are you sure you know the area of your home? Or the house you're buying?

It is essential to know that, in Portugal, there are two measures of common use when referring to residential real estate. Unfortunately, these measures are sometimes almost randomly operationalized by owners and (some) agents, causing you to occasionally face two or more properties using different criteria and orders of magnitude. When this happens, any objective effort at comparison is immediately biased.

The area is one of the most important variables in searching for a home. It helps us to quantify and perceive the housing conditions of a property, but this variable also projects the expected amount by which a property is to be traded, through the value per square meter.



Gross Private Area (G.P.A.) [Área Bruta Privativa (A.B.P.)]

“This is the total surface area measured by the outer perimeter and axes of the walls or other elements separating the building or fraction, including private enclosed balconies, private cellars and attics with the same use as the building or fraction (…)” (Article 40, CIMI; the Municipal Tax on Property Code).

The G.P.A. is the area measured “to the internal face of the external walls”. This area is used to estimate the equity value of the property, which, in turn, is used to calculate the tax amounts. This means that, when acquiring a housing fraction, the buyer is not only buying the living space but the structure that surrounds it. It should be noted that G.P.A. does not include outside areas, storage rooms and parking spaces

Includes: rooms, bedrooms, corridors, halls, kitchens, bathrooms, enclosed balconies, cellars and attics, vestibules and storerooms, sanitary facilities, internal paths; 100% of the area of the internal walls, the walls that constitute the façade and the walls that confine with common spaces; 50% of the area walls adjoining to other fractions.

Excludes: open balconies, terraces, garages and storage rooms.

In which documentation can you find the Gross Internal Area? At Caderneta Predial Urbana (issued by the National Financial Bureau).



The G.P.A. is also the concept closest to what could be considered the "official area" of housing in Portugal.

For two reasons, firstly, it is on this basis that the most relevant studies on housing prices are build up. When Statistics Portugal reports that the median square meter price in a given municipality or parish in the country is 3,000€/sqm, it is the G.P.A. that is being considered.

Just as relevant, the bank appraisal is also based on the value of the G.P.A. More, even if the house has undergone alterations if they are not duly registered and reflected in the value shown in the caderneta predial urbana, the appraiser will tend to ignore (or value in a residual way) any increase or extension.



Net Internal Area (N.I.A) [Área Útil (A.U.)]

“The sum of the areas of all the living compartments, including lobbies, internal corridors, sanitary facilities, storage rooms, other compartments with a similar function and cabinets on the walls, and it is measured by the inner perimeter of the walls that limit the home (…)” (Article 67, RGEU; the General Law on Urban Construction)

Except for some storage space (i.e., wardrobe or closet) or sanitary facility (i.e., bathtub or washbasin), the usable area corresponds to the floor space that can be occupied within a fraction.

Includes: all that is comprised in the G.I.A., excluding any walls.

Excludes: open balconies, terraces, garages and storage rooms.

In which documentation can you find the Net Internal Area? At the Energy Performance Certificate and, very likely, in the Plans of the house.


Conclusions and advice

The Gross Private Area is the private and covered area of a house, calculated together with the area of the walls. Traditionally this is the value used to calculate the cost per square meter of a house.

The Net Internal Area is the part of the house that is destined to be furnished and inhabited. It corresponds to the number of square meters available to you.

Always question the promoters of a given property about the published area values. There are two particularly common cases when searching for real estate ads on broker websites and portals:

1) References to the Net Internal Area with values that correspond, in fact, to the Gross Internal Area. Bear in mind that the N.I.A may be equivalent, on average, to values from 80% to 90% of the G.P.A., depending on the type and age of the construction;

2) Houses with open balconies and terraces, where the areas of these external spaces are erroneously taken in account to quantify the Gross Internal Area.

Always request the documentation of a property before making any formal purchase proposal.

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