Professional advice
Cleaning your façade: pressure washer, bleach or a professional?
In brief
A pressure washer used incorrectly can gouge render, damage joints and let water into the wall. Bleach works on green growth but attacks window frames and plants, and must never be mixed with other products. The right method depends on the surface: suitable pressure, a product chosen for the material, a test on a small area.
The risks of high pressure
- On render or roughcast, a jet that is too powerful gouges the surface and leaves marks.
- On brick and stone, it can wash out the joints and encourage water ingress.
- Used at height on a ladder, it is dangerous for the person holding it.
What about bleach?
Diluted, it kills algae and green marks. But it can discolour some surfaces, attack window frames, metals and plants, and must never be mixed with another household product, as this can release dangerous gases. Specific façade cleaners are more suitable.
A professional's method
- A test on a discreet area to set the pressure and choose the product.
- Protection of window frames, light fittings and plants.
- Cleaning from the ground, with a pole, without scaffolding when possible.
- Careful rinsing and, if the surface allows it, a water-repellent or anti-dirt treatment.
Who pays for façade cleaning?
Cleaning and renovating the façade are the responsibility of the owner, or of the co-owners in an apartment building. Some French towns require periodic façade renovation: check with your town hall.
Written by Gautier Lauwerier, President of Maison Owlaris, in Steenvoorde. Maison Owlaris works throughout Hauts-de-France. Updated in October 2026.
Frequently asked questions
Your questions.
Can a façade be cleaned without scaffolding?
Often yes: telescopic poles let us reach the top of walls from the ground. The method is decided after seeing the façade.
How long does a cleaned façade stay clean?
It depends on the exposure. A water-repellent or anti-dirt treatment applied after cleaning helps keep the result for longer.
Do you clean the brick façades of the north of France?
Yes, brick is very common in Hauts-de-France. We adapt the pressure and the product so as not to damage the joints.
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