Built area and usable area

Built area: what is inside the figure

Built area, superficie construida, is measured to the outer face of the external walls, and everything inside that outline counts: rooms, partitions, wall thickness, columns, ducts. It is the figure that normally appears in a price list and in the deed of division of the building.

It comes in two versions, and a listing seldom says which. Built area without common parts covers the dwelling alone; with common parts it adds the unit’s share of the entrance hall, stairs, lift shaft, corridors and plant rooms. The second is larger, and in a building with generous common space the gap is not small.

The area recorded in the land registry, and visible in the nota simple, is normally a built figure — one reason a tape measure never agrees with the deed.

Usable area: the floor you walk on

Usable area, superficie útil, is measured inside the enclosing walls to their inner face, so partitions, wall thickness and shafts drop out. Conventions differ at the edges — a built-in wardrobe, a room under a sloping ceiling — so ask how the figure in front of you was produced.

The two answer separate questions. Usable area tells you what the dwelling will hold; built area tells you what you are buying and what the deed will say. Neither is the honest one.

The ratio between them is informative in itself. A compact plan with few partitions loses little from built to usable; one with thick structural walls, a long corridor and several risers loses much more. Compare the ratio across two flats of the same built area and you see which layout is more efficient.

Terraces, balconies and storage

Open and semi-open space is normally counted at a fraction of its measured area when it is added into the figure for the dwelling, on the reasoning that a terrace is not worth the same per square metre as a living room. The fraction is not a national rule: in Spain it follows the habitability rules of the autonomous community and the project’s own convention. The widespread convention is to count a covered terrace at half and a fully enclosed one in full, but it is a convention, not a statutory figure, so ask which was applied. Roughly, in order of how much is counted:

• an open balcony, the smallest fraction, or shown on its own line and not added at all;
• a terrace covered by the floor or roof above, a larger fraction;
• a glazed gallery closed on all sides, often counted in full;
• a roof terrace reached only from the dwelling, usually a separate line, and sometimes a common element the flat holds exclusive use of rather than owning;
• a parking space and a storeroom, separate units with their own areas and often their own registry entry.

So do not ask for the total alone: ask for the measured area of each outdoor space and the fraction applied, and the total becomes checkable.

The distinction reaches past the price list: a roof terrace that is a common element with exclusive use cannot be altered at will, and a change to it can need a decision of the community. Your notary will tell you which of the two you are being sold.

Common parts and the participation quota

Everything outside a unit is common: structure, roof, facade, entrances, lifts, corridors, pool, grounds, plant rooms. Each unit holds an undivided share of it, and that share is the participation quota written into the deed of division.

The quota does two jobs at once: it allocates the common costs between the units and it is the basis on which the share of common parts is added to a built area. The same document that fixes what you pay each month fixes the larger of the figures quoted to you.

Why one apartment shows two figures

Two listings for one flat can disagree without either being dishonest. One may quote built area with common parts and the other without. One may fold the terrace in at a fraction and the other leave it out. One may work from the architect's drawing and the other from the survey of the finished building, and rounding adds a metre here or there.

From the plan means the figure is taken from the design before the building exists. After completion, the as-built survey and the declaration of new work fix the final areas, and they can move slightly against the design. A contract for an unbuilt flat should say which figure binds the parties and what happens if the delivered area falls outside the tolerance it allows; read that clause before the reservation, not after.

What you can claim if it does depends on something the sales conversation never mentions. The Civil Code distinguishes a sale by unit of measure, where a stated price per square metre is of the essence and a shortfall gives the buyer a remedy, from a sale of a determinate thing as a whole, where the agreed price stands even if the measurement differs. Which of the two your contract is written as decides the argument, so have it read before it is signed.

SAVO states built area and usable area separately for its own apartments and puts terrace area on its own line, so the figures can be set against another developer without recalculation. When you compare two offers, establish which definition each seller used before concluding that one flat is bigger. This article explains measurement conventions in general and is not technical or legal advice on a particular dwelling.