New ways in stone protection – feel-good factor, material protection and energy saving in one!

Long-term hygiene as a flagship of the »City on the River«


In order to permanently protect their new sandstone benches at the riverside area »Neckarlauer« against dirt, bird droppings, chewing gum, graffiti as well as algae and moss, the city of Heidelberg/Germany had the stone surfaces refined with the environmentally friendly barrier protection from Nanopool. The invisible coating against dirt adhesion and weather residues ensures that natural dirt on the surfaces is simply washed off by rain. This makes the recreation area on the riverbank even more attractive and at the same time it helps to save water, thus supporting energy-saving measures.


Moisture and moss pads can form a wafer-thin biofilm on stone surfaces, which permanently damages the substrate and delays the drying of the stones. The professional NP® coating prevents this and thus increases both material protection and the feel-good factor in a treated area. The treated surface is not changed either optically or haptically.



Natural stone remains breathable


In contrast to many common stone impregnations, the NP® barrier gives natural stone its new, repellent properties without sealing it airtight: The coating is so ultra-thin that it encloses the individual grains and therefore does not seal pores and joints.


As a result, the stone dries quickly and without restriction if moisture enters through the underside. This was also confirmed in an official report by the Institute for Stone Conservation (Instituts für Steinkonservierung e. V.): In cooperation with Dr. Tombers & Partners – Society for structural damage research, material testing and environmental analysis (Gesellschaft für Bauschadensforschung, Materialprüfung und Umweltanalytik mbH) the water vapor diffusion resistance number µ for the Nanopool product was determined. The results showed that despite the high protective effect of the NP® barrier layer, the water vapor permeability of the treated sandstone sample corresponds to that of an untreated stone.



Protection against driving rain and freeze-thaw


Natural stone can be severely damaged by weather over time. Among other things, the capillary effect of driving rain leads to a moisture penetration of the stone, which not only causes mould and algae infestation, but also gradually causes the substrate to burst open during freeze-thaw cycles.


The NP® protective coating prevents this, as moisture can no longer penetrate the stone and the source of any changes in the material is therefore eliminated.


The nstitute for Stone Conservation (Instituts für Steinkonservierung e. V.) stated, among other things:


  • Studies on different stone samples show that the water-repellent effect of NP® Stone Protect is permanent and that the drying of the stone is not impaired if moisture penetrates the back.


  • In a sample that has been stored for several years, no changes in the stone surface have been found so far. Untreated stone samples and those treated with conventional water repellents sometimes show microbial growth, while the samples treated with the (NP®) spray do not.


  • With the help of the alternating freeze-thaw test it was shown that the effectiveness of the NP® product is still given even after 100 test cycles.


  • The adhesion of moss and algae formation is prevented without biocidal additives.