The brick facade is bricked with mortar. The mortar is composed of different chemical elements. For example, cement contains some free lime or calcium hydroxide Ca(OH)2 or other additives, depending on the manufacturer of the mortar. Salting is most likely to occur if the brickwork is built during the cold season of the year, i.e. from October to April. If the brickwork is laid in the cold season, these soluble compounds may come out on the wall/facade surface with the moisture as the brickwork dries after bricklaying. Moisture evaporates from the surface of the wall, but these soluble compounds that come with the moisture cannot evaporate. They therefore remain on the wall in the form of white spots – salts.
If the brickwork is built during the warm season, these compounds can react with each other and the CO2 in the air to form insoluble compounds that cannot migrate with the moisture and therefore do not reach the surface of the wall. Consequently, no white spots are formed.
White patches can also form if there is no air barrier between the brickwork and the facing wall, resulting in the brickwork being in contact with the facing wall. Depending on the material of the brickwork, the brickwork may then contain elevated moisture content and soluble compounds. As the brickwork dries, these compounds, together with the moisture, can be released into the brickwork and further onto the masonry surface.
However, if the object has to be refinished and there are white salts on the facade, these can be washed off with a pressure washer after re-curing. If this does not help, there are special facade cleaners such as Vincents Clean (fresh water) or Remmers Fassadenreiniger. The instructions given on the detergents must be strictly followed.
