In general, there is a big problem with sandblasting outdoors: Despite solid covers, the blasting material penetrates into all cracks and usually into adjacent areas, and is difficult to remove from there. For the facade or freestanding walls sandblasting is therefore generally problematic.
In addition, the wall could be damaged - especially with abrasive blasting material. This can not be avoided in many cases. By sandblasting, joint material may also be removed, after which the joints would have to be rehabilitated accordingly.
Dry ice blasting offers a good option for cleaning façades. Frozen carbon dioxide is used here as blasting material. When the ice particles hit, the dirt on a facade or masonry is embrittled (deep-frozen) and the carbon dioxide expands. As a result, dirt particles are simply blasted off.
The carbon dioxide becomes gaseous and dissolves easily in the ambient air. As a result, no blasting material remains, which would have to be disposed of later. The method is very gentle and also suitable for sensitive surfaces.
CleanLaser as an alternative
Particularly in the preservation of monuments, special backpack lasers or mobile devices are used to clean facades. The method is even more gentle than dry ice blasting. The intensity of the laser beam can be adapted very precisely to the respective material, with different lenses a very exact processing of surfaces is possible.
Soot, dust and other dirt can be removed in a targeted manner without damaging the substance. However, the procedure is still relatively new and hardly used outside professional restorers circles.
Sandblasting clinker is not possible. The method is conceivably unsuitable and can severely damage the very densely sintered surface of the stones and thus ruin the entire clinker facade.
Tips & TricksWith high-pressure cleaners, cleaning with many types of masonry also requires reduced pressure, especially to prevent damage to existing joints. In any case, get advice from a specialist before use, which you must pay special attention to.