The stains can also be related to rising (often for light colored tiles) and are then very difficult or maybe even impossible to remove. Dry aggressive grinding can sometimes reduce the stains but it will always stay very difficult.
In case of brown stains, there are two main sources :
- The stains are only present on some of the tiles and stop on the edges. It is likely that these tiles contain pyrite crystals which converted in iron oxide in the presence of water (during cleaning).
- The stains are present on several tiles. The stains are due to the rising of ferruginous particles in the concrete screed.
English
Intro:
The presence of stains on the floor has two possible origins. They may be due to the environment ( grease, wine, rust,…). If this is the case it is always possible to reduce them or to remove them completely through grinding and with various devices.