Damp checks before renting or buying a flat in Barcelona

The ten minutes that matter

Walk the flat in this order: north-facing and interior rooms, the bathroom without a window, the ceiling under any terrat, then the wall shared with the patio de llums. Damp here rarely announces itself in the middle of a sunny living-room wall.

Then ask three things: is there a current cèdula d’habitabilitat, has the building done its ITE, and what façade, roof or bajantes works has the comunidad approved, done or postponed? Those answers say more about the next two winters than anything visible on a dry July afternoon.

Where to look, and why it fails there

Where	Why it fails	Look for
North-facing and interior rooms	Coldest surfaces all winter	Speckling in top corners, marks behind a headboard or inside a fitted wardrobe, a wall cold to the hand
Bathroom with no window	Steam with nowhere to go	Dark grout and silicone, blistered ceiling, a rejilla that won’t hold a tissue
Ceiling under a terrat	Roof is a common element; failed waterproofing shows below first	Brown-edged rings, re-skimmed plaster, a repainted band along one edge
Party wall to a patio de llums	Shaded humid shaft, old risers, neighbours’ connections	Tide marks near the floor, bubbling paint, musty cupboards
Window reveals and sills	Thermal bridge, single glazing, old carpentry	Black in the reveal corner, stained sill, perished sealant
Bottom of ground-floor walls	Moisture drawn up through dense masonry	A horizontal tide line, white salt bloom (salitre), lifting skirting

British damp advice misleads here. The failure modes are not cavity walls and damp-proof courses but unheated single-glazed rooms, shared façades and neighbours’ leaks through party walls.

A freshly painted patch in one corner

Flats get repainted between tenancies, so one bright wall proves nothing. What earns a question is a patch stopping short of a corner, a wall painted while the ceiling was not, or new paint exactly where the table predicts a problem.

A whole product category exists for this: bloqueador de manchas, stain-blocking primer, made to stop a water mark bleeding through a new coat. It works — which is the difficulty: it removes the diagnostic signal without removing the water. Plastic emulsion over a still-damp wall does much the same, trapping moisture until the film blisters. So ask: “¿Se ha pintado esta pared hace poco? ¿Por qué?” Run a hand over it for a change in texture, and press for softness underneath.

What to smell for

A musty smell is often the first sign of mould (mold, in American English) somewhere you cannot see. A flat aired for an hour before you arrive smells of nothing, so go looking: fitted wardrobes, under the sink, the storage room, and the smallest room — revisited at the end, door shut throughout.

In one reported Barcelona decision (SAP Barcelona, 3 September 2019) a strong smell from damp hidden above a false ceiling, undetectable at the viewing, was held enough for a tenant to end a newly signed lease with no penalty — even though the landlord may not have known either. That is an Audiencia Provincial ruling from a secondary source, not binding doctrine: illustrative, not a rule to rely on.

The questions, and who to ask

Most Spanish advice on communities of owners cites the Ley de Propiedad Horizontal. In Catalonia it does not apply: propiedad horizontal sits in the Codi civil de Catalunya, Llibre V. Façade, roof, structure and shared installations are common elements (Art. 553-41), and the community must maintain watertightness — estanquidad — and habitability (Art. 553-44.1). A terrat under one flat’s exclusive use stays common: upkeep is the user’s, construction or structural defects the community’s, unless caused by misuse (Art. 553-43.4).

Ask	In Spanish	Why
Valid cèdula?	”¿Tiene la vivienda cédula de habitabilidad vigente? ¿Me la puede enseñar?”	Legally required to let or sell in Catalonia; a vague answer is information
History of damp?	”¿Ha habido humedades, filtraciones o goteras? ¿Cuándo, y qué se hizo?”	Fixes what is pre-existing before you take the property on
ITE done?	”¿El edificio tiene la ITE hecha? ¿Salió favorable o con deficiencias?”	Generally compulsory from 45 years of building age; visual only, so no hidden defects, but façade or roof deficiencies are a real signal
The minutes	”¿Puedo ver las actas de las últimas juntas?”	Approved-but-unexecuted works and repeat leak complaints surface here first
Works and levies	”¿Hay obras de fachada, cubierta o bajantes aprobadas o pendientes? ¿Hay alguna derrama acordada?”	What is coming, and for buyers what may still be owed

Buying: ask in writing, before signing, who is liable for works approved but not yet carried out. Renting: Art. 21.2 of the Ley de Arrendamientos Urbanos obliges you to tolerate conservation works that cannot wait, and if the works run past twenty days the rent drops in proportion to the part of the home you cannot use. Those twenty days are widely misreported as a deadline for the landlord to act; Spanish law sets none. More in who pays for mould in a rented flat and damp, your comunidad and your insurance.

What to photograph at handover

Art. 1563 of the Código Civil makes a tenant answerable for deterioration unless they can show it happened without their fault. A dated record made on day one answers that.

• Every wall of every room: wide shot, then close-up of anything at all
• Inside fitted wardrobes, and behind furniture you may move
• Window reveals, sills, silicone; bathroom ceiling, grout, extractor grille
• The bottom of every outside wall and the skirting behind it
• Any patch you asked about, even if the answer reassured you
• Meter readings and the cèdula

Ask for an anexo fotográfico attached to the inventario, dated and signed by both sides; if refused, email the photographs the same day and keep the sent message. Name any existing damp in writing, not verbally. If you later have to escalate, a burofax carrying both acuse de recibo and certificación de contenido proves what you said and when — a carta certificada proves only that an envelope arrived.

What a viewing cannot tell you

It is not a survey. You are looking at a decorated surface, on one day, in whatever season you happen to be moving.

Condensation is the honest gap. A north-facing bedroom that is dry in July can mark within weeks of the first cold snap: what produces the marks is the gap between indoor warmth and outdoor cold, and in a flat with no central heating and single glazing that gap does not exist in summer. See how condensation mould behaves in a Barcelona flat.

It is also the one damp type where responsibility is genuinely unsettled in Spanish case law. Some courts attribute it to how the occupant ventilates; others hold that a building’s poor ventilation, insulation or thermal bridging makes it the owner’s problem regardless; at least one appellate decision split the damage roughly in half. It turns on whether the home could be kept free of condensation with normal use — decided on expert evidence, not by a rule. Anyone telling you it is always the tenant’s fault, or always the landlord’s, is telling you what they would like to be true.

Insurance is no backstop. Spanish home policies are built around sudden, accidental escapes of water; gradual damp, condensation and rising damp are commonly excluded, and water through a worn façade is often treated as lack of maintenance.

If you want more than a viewing, an arquitecto técnico can inspect and report before you sign. NoMoho does not do purchase surveys: we work on visible mould and the condensation side of damp, so an established mark is damp wall repair territory.

This is general information about Spanish and Catalan rules in the public domain. It is not legal, financial or insurance advice, and NoMoho provides none of those. Damp disputes turn on their own facts and usually on expert technical evidence; the Oficines de l’Habitatge de Barcelona offer free legal advice.