Painting the facade or wall? Why you wash it first (and how)
Paint sticks to the wall, not to the dirt on top of it. Painting over green algae, soot or dust means painting over a loose layer: the new paint comes off with it. That is why a facade or wall is washed before it is painted.
What has to come off before the paint
- Green algae: they keep growing under the paint and come back through it (see green algae on the facade)
- Soot and pollution: the dark film stops the paint from bonding (see darkened facade)
- Old, flaking paint: washing loosens what is no longer attached, and the painter sees where to scrape
- Graffiti: remove it first, or it bleeds through the new paint (see graffiti on the wall)
How we wash before painting
For facade washing we use moderate pressure and an anti-algae product on render, and the right product on stone. On sound paint we do not strip the coating; where paint is already coming loose, the wash shows exactly where the problem is, which helps whoever will paint. Walls and fences follow the same process, under wall washing.
How long to wait before painting
The wall must be dry inside, not just on the surface. In dry weather one to two days is usually enough; after days of rain or on a north-facing wall, longer. The painter decides, depending on the paint: agree the washing date with them.
How much it costs
Facades from €7/m² (€120 minimum), walls and fences from €6.5/m² (€89 minimum), guide price on the site before you book. With a telescopic lance we reach about 9 to 10 metres from the ground, without scaffolding. If the house is for sale or rent, a wash alone already changes a lot, as we explain in washing the facade adds value.
Best time of year
Spring and early autumn: dry weather for the wall to dry and for the paint to cure. If you plan to paint before winter, see the autumn checklist too. Get the washing price in 60 seconds.