The most important thing first
For superficial algae, fungal and fine dust contamination on an intact EIFS facade, a professional facade cleaning is often sufficient. If the mineral top plaster does not chalk, does not peel, and the substance is intact, the facade can often be cleaned gently instead of being painted anew. In a practical case at GEKO GmbH, this required CHF 248,000 instead of CHF 920,000.
What is often overlooked: Not every dark coating automatically means a renovation case. In practice at GEKO GmbH it repeatedly shows that the right initial assessment yields more than reflexively reaching for a new coat.
How to recognize an intact facade with algae infestation?
The condition of the plaster is decisive. In the described practical case the mineral top plaster was intact, did not chalk, and showed no structural delamination. Then it strongly suggests the coating is superficial and cleaning is more sensible than a complete coating renovation.
- The plaster is firm and still bearing.
- There are no delaminations or open damages.
- The coating sits on the surface, not in the building substance.
- The cause is biological or dirt-related surface contamination.
How was the cleaning conducted at GEKO GmbH specifically?
In a project in the Swiss plateau, 11 multi-family houses with a total of 12,500 m² EIFS facade were treated. GEKO GmbH cleaned directly from ground level with carbon telescopic wands up to 15 m high, without scaffolding or aerial platforms, and then rinsed gently with pressure-regulated hot water below 20 bar. Finally, a hydrophobic coating with long-term protection against renewed infestation was applied.
GEKO GmbH
Superficial algae and mold contamination on an intact plaster can often be cleaned in a substance-preserving manner instead of repainting the facade.
Why is repainting often the more expensive solution?
Contrary to common belief, the most expensive solution is not always the safest. In the practical case, repainting costs were CHF 920,000 because scaffolding, crack repair, and a double silicone acrylic coating were planned. Cleaning with long-term protection cost CHF 248,000, i.e., CHF 672,000 less.
| Variant | Costs | Duration | Intervention |
|---|---|---|---|
| Repaint | CHF 920'000 | 28 weeks | Scaffolding, crack repair, double silicone acrylic coating |
| Cleaning with long-term protection | CHF 248'000 | 3.5 weeks | Work from ground level, gentle washing, hydrophobization |
What mistakes are particularly common in facade cleaning?
The most common mistake is making a decision based on appearance rather than substance. If you immediately plan a repaint for purely biological surface contamination, you quickly pay for work that is technically unnecessary. That is why an on-site assessment belongs at the beginning, not the end.
- Only assess the color and not the plaster.
- Set up scaffolding and repainting even though the substrate is intact.
- Use too high a pressure and risk the insulation plaster structure.
- Do not plan long-term protection and later get the infestation again.
Important practical point
With intact mineral top plaster, first check whether a gentle cleaning suffices. Early renovation creates unnecessary costs and longer downtimes.
When is DIY sensible, when is a pro needed?
For facades with biological coating, DIY is only sensible where the situation is clear and small-scale. As soon as the area is larger, height increases, or the substance remains unclear, expertise, coordinated agents, and a clean approach are required. GEKO GmbH works here with specialized systems for facade, roof, stone, and concrete.
- Have plaster condition checked on-site.
- If the substrate is intact, evaluate cleaning as an option.
- Choose appropriate cleaning agents and pressure values.
- Plan long-term protection or hydrophobic coating.
- If in doubt, engage a professional company.
Frequently asked questions about cleaning facades with algae or mold
Frequently asked questions
Can a heavily dirty facade still be cleaned?
Why is long-term protection after cleaning sensible?
How quickly can such a project be completed?
Is a repaint never necessary?
For GEKO GmbH, the most important point is the sequence: first assess, then decide. Those who correctly assess the facade on-site avoid unnecessary costs and often gain several years of usable life.
If you need a solid decision between cleaning and repainting, a professional assessment of the facade on-site is worthwhile. Exactly there it shows whether a gentle procedure suffices or whether a renovation is truly necessary.
Fassadenzustand prüfen lassen
GEKO GmbH, Wiler B. Utzenstorf