What to check about a building before buying in San Sebastián

Plenty of buildings from before 1941

The 2021 census counts 94,733 homes in the city. What sets Donostia apart from the other Basque capitals is how much of it is old: 8,737 homes are in buildings from 1900 to 1920 and, adding earlier ones and those from 1921 to 1940, 15,758 are in buildings from before 1941. The other big period was 1961 to 1980, with 35,555.

A century-old building is not worse for its age, but it may have load-bearing walls, timber or early joist floors, services renewed piece by piece and roofs repaired several times over. In such buildings the inspection and the owners' association's record of works say a lot, and a pending refurbishment can mean a large special levy (derrama) for each owner.

The building inspection in Gipuzkoa: where to find it

Throughout the Basque Country the building inspection (ITE) is compulsory for mainly residential buildings more than 50 years old and is renewed ten years after being filed with the city council, under Decree 117/2018. In Donostia, nearly half of all homes are in buildings from 1970 or earlier, which have already crossed that line.

The same decree sets up a regional register and states that access to its information is public, free and provided online. That register is Euskoregite: it has a building search, and the HOUSINGFAX report queries it from the entrance address. The Basque inspection reviews the foundations, structure, roof, façades and water systems, and also looks at accessibility and energy efficiency; the report shows the grade of each system and whether defects are recorded as fixed.

If the register shows that an inspection was due and none was filed, the report says so. Then ask the property manager whether one has been commissioned and whether the seller knows of works already approved at an owners' meeting: at these prices, agreeing in writing who pays for approved works is part of the negotiation.

Gipuzkoa's cadastre and the building data

Gipuzkoa keeps its own cadastre, and the Provincial Council publishes its geographic information on b5m, the province's spatial data portal, with street directory, neighbourhoods, buildings and maps. That is why a Donostia flat cannot be found on the national cadastre's website or with a 20-character Spanish cadastral reference.

HOUSINGFAX locates the entrance in the official Basque street directory and matches it with the b5m layers to get the building footprint and its local reference. The year of construction comes from the Provincial Council's building layer; where that layer has none, the report uses the indicative year held in Euskoregite and says so. In Gipuzkoa the report covers the whole building and does not estimate the price of one flat.

The Urumea, the coast and the Oria

Spain's national flood mapping system places four areas of significant potential flood risk in the municipality. Two belong to the Urumea: one shared with Hernani and Astigarraga, classed as river and sea flooding, and one inside the city. The third, named Donostia-costa, is coastal. The fourth is a stretch of the Oria described under Lasarte-Oria that the official overlay also places within the municipality.

A risk area does not make the whole city flood-prone: the ten-year flood zone crosses the municipality, but only overlaying the plot tells you whether a specific building sits inside a mapped zone. Check 10 of the report does that with the river and coastal zones from 10 to 500 years. It matters most for a ground-floor flat or a basement garage near the river or the sea.

Earthquakes and radon in Donostia

Unlike Bilbao or Vitoria-Gasteiz, Donostia does appear in the annex of the seismic standard NCSE-02, with a basic ground acceleration of 0.04 g, the lowest value the standard lists. Check 12 gives the value for the building. On radon, the municipality is not in zone I or II of the building code, though check 22 still places the building on the Nuclear Safety Council's radon potential map.

Where the report stops

The report gathers what official registers say, with source and date, and shows what is not on record. It does not enter the home and does not replace a technical inspection of the building; if the register records structural defects, have a surveyor see them before you sign the arras, the deposit contract that comes before the deed.