How to clean rising damp stains

Barrier against rising damp and saltpeter problems

In this post we are going to see one of the most common problems caused by humidity in the interior of houses, the saltpeter on walls caused by rising damp. And we will also see a product that will help us to treat these humidity problems.

One of the most frequent problems related to humidity is when saltpeter appear due to rising damp. What happens is that the water rises through the pores of the materials and on its way dissolves the mineral salts of the cement and concrete, and even of the plaster.

When this humidity with the mineral salts in solution reaches the interior surface of the walls of the house it evaporates, the mineral salts in solution crystallize, and as they grow they deteriorate the paint and even deteriorate the plaster. This problem usually appears in the lower part of the walls, causing a bulging and a very visible deterioration of the layers of paint and plaster, and crystallized salts are visible. Therefore, it is very easy to differentiate this problem from that caused by mold.

The first thing we must do is to use a scraper and a brush to scrape and remove all loose paint and plaster that is in poor condition, until a firm surface is achieved. Then I clean the entire surface well with a mixture of water and vinegar. This will help to remove any remaining salts on the wall. Thus, with the surface already clean, I can apply Xylazel damp-proof barrier solutions, a product that protects against moisture problems due to rising damp and due to leaks.

This is a bicomponent product, so I have to mix well, in equal parts, the two components that come in the package. I have to homogenize the mixture well and apply a coat using a brush or a roller. I let the product dry for two hours and apply a second coat. This will protect against rising damp, but because we scratch the surface and even remove part of the plaster, after applying (and allowing to dry) the damp-proof barrier it may be necessary to fill the repaired surface with plaster to leave a smooth surface before painting. In these cases it is advisable to use a product of the same brand.
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