What is it?
Efflorescence is a deposit of soluble salts and bases, usually white in color, that sometimes appear on the surfaces of masonry or concrete construction. Although it may be an aesthetic concern, efflorescence will not affect structural performance.
What causes it?
A combination of circumstances causes efflorescence. First, there must be soluble compounds in the masonry. Second, moisture must be present to pick up the soluble salts and carry them to the surface. Third, some force—evaporation or hydrostatic pressure—must cause the solution to move. If any one of these conditions is eliminated, efflorescence will not occur.
Since many factors influence the formation of efflorescence, it is difficult to predict if and when it will appear. However, to reduce the probability of efflorescence occurring in masonry construction, it is necessary to minimize the amount of soluble salts and moisture present in the masonry. Of the two, moisture is the more easily avoided.
How is it removed?
Most efflorescing salts are water soluble and many will disappear with normal weathering unless there is some external source of salts. In general, most efflorescence can be removed by dry-brushing followed by flushing with clean water. There also are a variety of commercial cleaners available which may be effective for efflorescence removal. However, some of these chemicals may not be safe for the surrounding vegetation.
Calcium carbonate efflorescence, on the other hand, is extremely difficult to remove. It appears usually as a flat white deposit and in the worst cases forms a hard white crust. Any effective methods of removal can alter the texture of the block to such an extent that it is necessary to treat the entire area and not merely the affected regions.
If you are unable to remove the efflorescence with light brushing, it may be necessary to contact a professional contractor. Professional contractors have the equipment and environmentally friendly chemicals to safely clean brick exterior surfaces.
The KC Restoration team has the expertise, materials, and procedures to provide exterior deep cleaning services for any type of property. Free consultations are provided for any type of cleaning or restoration project.