Black mould in bathroom in El Masnou: causes, cleaning and lasting fix
Resumen rápido
Bathroom mould is usually condensation, not a leak.
¿Qué está pasando?
Shower steam pushes humidity above 80%.
Causas más probables
Poor ventilation after showering
altaSmall fan or blocked duct.
Failing silicone seals
altaAfter 3-5 years it loses its biocide.
Thermal bridge on outer wall
mediaBuildings without insulation have cold corners.
Pasos de diagnóstico
- 1
Clean with diluted bleach
Spray, wait, scrub.
⚠ Parada de seguridad: Never mix bleach with ammonia. - 2
Replace blackened silicone
Cut out and apply sanitary silicone.
- 3
Improve post-shower ventilation
Run the fan 15-20 min after.
Cuándo llamar a un profesional
Call if it returns in 2-3 weeks or exceeds 1 m².
Coste orientativo en El Masnou
80–280 €
Silicone replacement and antimould primer.
Contexto local · El Masnou
El Masnou's climate has high humidity year-round.
El Masnou is a thin strip between the C-32 and the sea with two realities: the upper part (Sant Felip, Ocata-Alt) is single-family homes with views, and the lower part (Centre, seafront) is 1960s–80s flats whose balconies face the N-II. Salt exposure is high: any external locksmithing or blinds get a marine treatment. The upper area drives periodic maintenance (garden, pool, heat pump); the lower area drives full refurbs that open up closed layouts. Parking is OK uphill, tough near the Renfe station.
- Comarca: Maresme
- Población: 23.579 hab.
- Parque de vivienda predominante: unifamiliar
- Año medio de construcción: 1985
- Códigos postales: 08320
Frente marítimo elegante con casas de indianos, mezcla de unifamiliares y bloques modernos.
Preguntas frecuentes
Is bathroom mould a health risk?
For asthmatics and young children, yes.
Does bleach kill mould completely?
Surface only — if it penetrated it returns.
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Más sobre Damp, mould and paint
Sources and regulation
- CTE DB-HS 1 — Protección frente a la humedad — Código Técnico de la Edificación