- Three conditions must exist simultaneously for efflorescence to result:
1 Soluble salts must be present within the masonry assembly
- Water must come in contact with the salts to form a solution
- The salt solution must have a path to migrate to a surface where the water can evaporate
Reducing Soluble Salts
Soluble salts may be present in masonry units and mortar materials. They can be carried into the wall with rainwater or absorbed with groundwater. They can be introduced with admixtures to mortar or with solutions used to clean new masonry.
With conventional masonry construction in wet climates, water penetration cannot be completely eliminated, but with proper design and workmanship, it can be reduced.
Clear water-repellent coatings sometimes are recommended to reduce or prevent efflorescence, but their use can cause more problems than it solves.
Most true efflorescence can be removed by dry brushing, then flushing with clean water. A mild muriatic acid solution (1 part muriatic acid to 12 parts water) may help to remove heavy accumulations.