Facade cleaning is one of the maintenance-intensive trades in building maintenance. Many owners underestimate the complexity: not every method is suitable for every material, and incorrect cleaning procedures cause long-term damage that is more expensive than the cleaning job itself. Providers advertise speed and price – but often conceal risks and alternative procedures.
Which soiling requires which method
The first mistake begins with diagnosis. Homeowners often call a service provider without knowing whether the facade merely carries surface dust or whether algae, moss, soot, or salt efflorescence are present. Each type of soiling requires its own method. Dust deposits can be removed with low pressure and mild detergent. Algae and fungi require biocidal pretreatments, which in Germany may only be applied with proof of expertise according to the Biocidal Products Regulation.
Soot and oil residues – typical on facades near industrial areas or along heavily trafficked roads – require chemical emulsifiers that must be matched to the respective binder of the facade paint. Lime-containing efflorescences, on the other hand, react acidically and must not be treated with alkaline cleaners, otherwise discoloration occurs.
High-pressure cleaning: Fast, cheap – and often harmful
The majority of service providers use high-pressure cleaners with pressures between 80 and 150 bar. The procedure is fast, requires little personnel, and appears effective at first glance. But this is precisely where the problem lies: high pressure not only removes dirt but also wears away the top layer of facade paint. With mineral plasters, the jet can open the pores and permanently alter capillary action. Water penetrates deeper, frost damage increases, algae formation accelerates.
Particularly critical is the use on thermal insulation composite systems. The top plaster layer is often only a few millimeters thick, beneath it lies the reinforcement mesh. Too much pressure can expose the mesh or detach the plaster layer from the insulation material. The result is cracks, moisture ingress, and in the worst case mold behind the insulation. Nevertheless, many providers advertise "gentle high-pressure cleaning" – a contradiction in itself if no differentiated pressure adjustment and nozzle selection takes place.
Low-pressure and sponge methods as an alternative
Specialist companies increasingly use low-pressure systems with a maximum of 30 bar. In combination with rotating brush attachments or microfiber sponges, they remove soiling mechanically without wearing away the surface. These methods take longer and cost more per square meter, but preserve the substance. For sensitive facades – such as heritage-protected buildings with historic lime plaster – dry cleaning with sponges or laser technology is the only permitted method.
Laser methods remove soiling through short, high-energy light pulses. They leave no residue, work without water, and do not affect the original substance. However, costs are 5 to 10 times higher than conventional methods and are only justified by heritage protection requirements or particularly sensitive surfaces.
What facade cleaning really costs
The price range is enormous and depends on method, degree of soiling, accessibility, and facade material. Simple high-pressure cleaning starts at 5 to 8 euros per square meter. This includes travel, scaffolding or aerial work platform, and cleaning agents. Low-pressure methods with manual follow-up work cost 12 to 18 euros per square meter. Biocidal treatment for algae infestation adds another 3 to 5 euros.
Scaffolding costs are often quoted separately and add 6 to 10 euros per square meter. For multi-story buildings without scaffolding options, aerial work platforms are used, with daily rates between 250 and 600 euros. For a typical single-family home facade with 150 square meters, the total cost ranges from 1,200 to 3,500 euros – depending on method and accessibility.
Many providers calculate lump sums and do not transparently identify additional services such as window frame cleaning, base coating impregnation, or follow-up treatment with water-repellent agents. Homeowners should insist that the quote lists every item individually. This is the only way to compare whether an apparently cheap offer actually includes all necessary services.
Hydrophobization: Useful protection or marketing promise
After cleaning, many service providers offer hydrophobization. A silane-based impregnating agent is sprayed onto the facade, making it water-repellent. The principle sounds plausible: less water means fewer algae. In fact, the procedure works, but only under certain conditions.
Hydrophobizations last between 3 and 8 years depending on product and weathering. They are effective on mineral plasters and clinker, less so on dispersion paint, which already has low water absorption. It becomes problematic when hydrophobization is applied to an already damaged facade: cracks and open joints remain, moisture continues to penetrate but can no longer diffuse outward. The result is accelerated material loss.
Reputable providers first test the absorbency of the facade with a water absorption test and document existing damage. Anyone selling hydrophobization as a flat "all-round protection" without assessing the original condition is working unprofessionally.
What clients should consider when selecting a provider
The facade cleaning market is largely unregulated. There is no master craftsman requirement, no certification requirement, and no binding quality standards. Anyone can operate as a service provider with a high-pressure cleaner and a van. That is why the selection is crucial.
Reputable providers conduct an on-site inspection before preparing an offer and document the type of soiling, facade material, and pre-existing damage. They disclose the cleaning method, name the products used, and point out possible risks. A written quote should contain at least the following points: cleaning method, pressure, chemicals (with safety data sheets), scaffolding costs, insurance certificate, and realistic scheduling.
Businesses with membership in a professional association or ISO 9001 certification generally offer higher quality standards. Liability insurance is also important: it should cover damage from improper cleaning up to at least 2 million euros. Many discount providers work without adequate insurance coverage – in case of damage, the owner bears the costs.
When cleaning is worthwhile – and when it is not
Not every dirty facade needs to be cleaned. Surface dust and slight discoloration are optical defects but do not impair function. Cleaning is worthwhile if biological growth attacks the surface, if salt efflorescences indicate moisture problems, or if soiling reduces thermal insulation performance – such as with heavy soot deposits.
In many cases, a complete repainting is more economical than expensive cleaning. If the facade paint is already chalking, has cracks, or the primer no longer adheres, cleaning only marginally extends the lifespan. Then the painter should refinish the facade – possibly after repairs with filler and a new primer coat.
For homeowners planning long-term maintenance strategy, collaboration with a specialized painting company is worthwhile. Many companies offer maintenance contracts that include regular inspections, minor repairs, and cleaning if needed. This costs less per year than emergency cleaning after years of neglect.
Regional peculiarities: Vienna as an example
In Vienna, numerous service providers advertise facade cleaning as their core service. Urban conditions – high fine dust pollution, dense construction, frequently heritage-protected old buildings – require adapted methods. Historic facades with stucco decoration or stucco luster may only be cleaned with low pressure and pH-neutral products. Nevertheless, many providers offer flat-rate prices without differentiation.
Those looking for a service provider in Vienna should check whether they can demonstrate experience with heritage-protected objects. The Municipal Department 19 (Architecture and Urban Design) provides recommendations for heritage-appropriate cleaning procedures. For old buildings with mineral plasters, advance consultation with the building authority is often required.
Conclusion: Transparency and expertise decide
Facade cleaning is not standard work. It requires material knowledge, adapted methods, and honest damage analysis. Homeowners should not choose the cheapest provider but rather the one who inspects the facade in advance, discloses the method, and points out risks. Those who forgo high-pressure cleaning and invest in gentle low-pressure or sponge methods extend the lifespan of the facade by years and save costs in the long run.
A central role is played by painting companies that not only clean but also understand the overall facade system. They recognize when cleaning is sufficient and when renovation of the old building facade is necessary. For owners who want to preserve their property long-term, collaboration with a specialized company is the most economical solution.