Green algae or mildew on siding — Madrid, Madrid
Green or black streaks on vinyl, wood, or fiber-cement siding are usually algae (Gloeocapsa magma) or mildew colonies fed by moisture and shade. Left alone they trap moisture against the surface, accelerating rot in wood and degrading paint. A professional pressure washing ($200–$500 for an average home exterior) removes these growths in 2–3 hours using a soft-wash technique — low pressure (under 1,500 PSI) with a sodium hypochlorite or oxygen bleach solution that kills spores without damaging siding. Standard high-pressure washing can force water behind siding laps on vinyl and splinter softwood grain, so soft-wash is the industry standard for building exteriors.
Who to call
For this problem in Madrid, call a: Schoonmaker
Vind een Schoonmaker in MadridSymptoms to look for
- Green, black, or dark streaks on siding that don't wash off with a garden hose
- Siding feels slimy or slippery to the touch in shaded areas
- Discoloration worsens on north-facing walls or under trees
- Musty outdoor smell near the house foundation
Spoeddienst in Madrid
Emergency services in Madrid respond within 30–75 minutes in the central districts. Callout rates run €55–€140 plus €45–€75/hour including IVA — among Spain's highest after Barcelona. Winter cold snaps drive burst-pipe and heating-failure surges that can stretch waits; verify the contractor is a registered instalador autorizado with the Comunidad de Madrid before granting entry.