Black mould in bathroom in Cornellà de Llobregat: 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 Cornellà de Llobregat
80–280 €
Silicone replacement and antimould primer.
Contexto local · Cornellà de Llobregat
Cornellà de Llobregat's climate has high humidity year-round.
Cornellà de Llobregat grew fast between 1965 and 1985 and most of its buildings fall in that bracket: 6–10-storey blocks in Centre, Almeda and Sant Ildefons. The big recent change is Next Generation-funded refurbs, mostly heat pumps and external wall insulation; our installers process the grants and sign the energy certificates. We still find old town-gas inlets in kitchens that need auditing before any work. Cornellà has decent loading zones and ample block parking, which keeps long-day jobs cheaper than dense L'Hospitalet or Santa Coloma.
- Comarca: Baix Llobregat
- Población: 88.224 hab.
- Parque de vivienda predominante: piso-moderno
- Año medio de construcción: 1976
- Códigos postales: 08940
Núcleo de Baix Llobregat con bloques densos en Sant Ildefons y crecimiento reciente en el área del Walden.
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.
¿Prefieres que vayamos nosotros?
Diagnóstico y presupuesto en Cornellà de Llobregat normalmente el mismo día.
Pedir presupuesto gratisProblemas relacionados en Cornellà de Llobregat
Más sobre Damp, mould and paint
Sources and regulation
- CTE DB-HS 1 — Protección frente a la humedad — Código Técnico de la Edificación