Saltpetre is formed very quickly in my boiler room especially around the flue gas duct; it goes up the walls up to the 2nd floor and goes inside. Is it dangerous? In particular, can this cause a fire in the duct? Can we treat it yourself and how?
The presence of saltpeter is due to the side effects of capillary moisture rising in the materials, especially in old farm premises. Saltpetre is a residue of the development of bacteria that feed on ammonia from the combination of soil water and potassium carbonate contained in the walls. The whitish residue you notice results from the migration of mineral salts into the masonry, then from their crystallization by evaporation of the water that transports them. The heat can further accentuate the phenomenon, since it accelerates evaporation.
Although saltpeter is the basis of the manufacture of gunpowder, I do not think you risk a fire. Before treating your duct and your wall you will have to find the cause of the rising damp, then you can pass a SALTPREP TREATMENT from Dip'Etanch, for example. You can also consult our sheet "FIGHT AGAINST SALPETRE" by Dip'Étanch.
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