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What are the causes for stains in the MORTEX® product and how to avoid them ?
Causes of staining
When the MORTEX® coating is applied with a highly textured finish, resulting in the formation of micro-cavities of varying sizes, liquids (grease, oil or other substances) may penetrate through these openings.
These areas are indeed vulnerable points for the coating and its protection. To prevent any infiltration, it is essential to treat these cavities carefully. During standard application of protective products (varnishes, oils, etc.) using
a roller or brush, these products generally do not penetrate the cavities due to their viscosity. It is therefore essential to work them in by tapping with a brush or a paintbrush, in order to treat both the edges and the base of these areas properly.
When these cavities are not protected, lateral capillary action may occur beneath the surface protection, causing stains in the substrate. In this case, the substrate can only dry through the small openings of the micro-cavities, whilst oily substances remain trapped and cannot escape.
For so-called ‘technical’ layers (floors, showers, wet areas, etc.), the presence of an open-pored substrate or cavities already indicates a shortcoming in the application process. This weakness compromises the system’s waterproofing and promotes the build-up of dirt in these sensitive areas.
The fact that stains appear locally rather than across the entire surface demonstrates that the protective coating (varnish or other) is effective where it has been correctly applied. Stains only appear in areas that are insufficiently protected.
It is therefore essential to dab the varnish or protective coating into all untreated micro-cavities. The presence of such cavities must, in all cases, be avoided as far as possible.
Note that apparently smooth surfaces may exhibit the same type of problem if the protective coating has been applied incorrectly or insufficiently.Proper application to prevent the appearance of stains
It is strongly recommended that a preliminary sample be produced and approved to determine the most suitable finish (smooth, textured, etc.) depending on the intended use of the project.
Example: for a shower and/or worktop, a smooth finish is always recommended to minimise the risk of dirt build-up and to facilitate maintenance.
It is also important to bear in mind that certain micro-cavities may be interconnected at their bases. It is precisely these areas that encourage the accumulation of grime such as dirt, soap residue, cleaning products, grease, hair dye, flour, butter, etc. Micro-cavities also create potential pathways for water penetration.
It is therefore essential to seal surfaces properly, minimising the formation of significant micro-cavities and applying protective coatings in strict accordance with best practice, in order to ensure the durability, aesthetic appeal and ease of maintenance of the coating.