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Problem

Mould on walls in Barcelona

Dark marks or blackening on a wall in your Barcelona flat — this page helps you understand what you are seeing and decide what to do next. You can write on WhatsApp with photos, in English.

Send photos on WhatsApp

You can write in English — we reply in English. We usually reply quickly. If we are on a job, it may take up to 2–3 hours.

About this problem

Where it usually appears

What to look at

When to send photos

Where mould usually appears

In Barcelona flats it most often shows up in familiar places:

  • corners facing the street, especially at the top
  • party walls that feel colder to the touch
  • behind wardrobes, headboards and tightly placed furniture
  • near a window, balcony or interior courtyard
  • on walls that were painted before and the mark came back

In many of these spots the wall is colder than the air, air circulates less easily and moisture settles — and mould follows.

What to look at

Three simple checks before you do anything:

  1. Paint. If it holds well, the case may be superficial. If it has bubbled, peeled or comes away, wiping alone is not enough.
  2. Size. A small mark and half a wall turning dark are different stories.
  3. History. First time, or has it returned after cleaning or painting? A repeat is a sign the issue is not only cosmetic.

Together, that usually points you in a sensible direction without pretending one photo explains everything.

Three common situations

  • Mould on sound paint. Treatment and attention to the corner, furniture and ventilation may be enough.
  • Mould with peeling paint or a damaged wall. Treatment plus restoring the base before painting is more typical.
  • A wall affected by damp without an obvious dark mark. The problem is already in the wall’s condition — a different conversation.

One word, “mould”, can hide very different cases.

Which service may fit

If the main issue is a mark on the wall, people usually start with mould removal in Barcelona. If the wall is badly affected, removal together with repair before painting is decided case by case.

Mould in a bathroom — on the ceiling, in joints, in corners — is better covered on the bathroom page: the context is different there.

Why painting over it rarely helps

Paint over a mark can look even for a few weeks, but it does not touch what caused the mark or prepare the base. The mark often returns on the new colour.

If it keeps coming back or paint will not hold, it is more useful to ask than to paint the same spot again. See mould keeps coming back after cleaning for a calmer next step.

When to send photos

Usually enough:

  • a wide shot of the wall — light, height, furniture
  • a close-up of the mark — no flash, in focus
  • a few words — when it appeared, whether the wall feels cold, whether you cleaned or painted

Behind furniture — move it and photograph the wall. Near a window — a frame that shows both the window and the wall.

One photo cannot name the exact cause of damp or promise the mark will not return. Photos are to sort the situation out, not to close it blindly.

With photos and a short note — contact. If it is already clear you need wall work — mould removal. Home — /en/.

What to know before starting

What to know before starting

Mould on a wall can look different. Photos help you see where to start — without unnecessary worry.

More on this topic

Related pages

When the picture is clearer — move to a service, a guide or write straight away.

FAQ

Frequently asked questions

Short answers. Question not listed — write on WhatsApp in English.

Can I write in English?

Yes. We read WhatsApp ourselves and reply in English.

What photos should I send?

A wide shot of the wall and room, a close-up of the mark without flash, and a few words: when it appeared, whether you cleaned or painted it. If the mark is behind furniture, move it and photograph the wall.

Why does painting over the mark usually not help?

A new coat can look flat for a while, but it does not remove the cause. After a few weeks the mark often returns on top of fresh paint.

Mould in a cold corner — what does that mean?

Often the wall in a corner is colder than the air and moisture settles on the surface. That is not a full explanation on its own — but a hint to look at the corner and ventilation, not only the mark.

Can you name the exact cause of damp from one photo?

No. A photo shows the surface condition and helps suggest a sensible option. The exact cause of damp is fairer to assess on site.

Contact

Send 3 photos on WhatsApp

A wide shot of the room, a close-up of the mark, and a few words about what you see. We reply in English.

If the photos show a visit is needed, we can arrange a free look in Barcelona.

You can write in English — we reply in English.

Artyom — Última actualización: 16 de junio de 2026