Efflorescence Treatment, Cleaning & Prevention

Efflorescence, a natural phenomenon, occurs when soluble salts and other water-dispersible substances emerge on the surface of natural materials. It is triggered by low temperatures, moist conditions, condensation, rain, dew, and the application of water on the surface of fresh concrete to aid troweling. Efflorescence may manifest shortly after exposure to moisture or cool conditions or gradually, particularly when it originates from within the surface or from the subgrade. This indicates that moisture is infiltrating the surface and suggests an improper drainage problem.

Any material containing Portland cement can lead to efflorescence. The most common reaction takes place when calcium hydroxide (lime), generated in the hydration reaction of Portland cement (approximately 140 pounds per cubic yard of concrete), is conveyed by water to the surface through capillaries in the concrete. There it reacts with carbon dioxide from the air, producing calcium carbonate (an insoluble substance) and water. However, efflorescence can also be caused by hydroxides and sulfates of sodium or potassium, which are much more soluble in water than calcium and form efflorescence more rapidly. These salts can originate from cement, aggregates, water, or admixtures.

Efflorescence is typically white but can vary in color and may be more noticeable on darker colors than on white or light gray due to the contrast. A mere 0.2 ounce of calcium carbonate per square yard of surface is sufficient to cause a significant color change. Some forms of efflorescence are challenging, if not impossible, to remove, while others are easily removable, particularly if addressed promptly after formation.

Left untreated, efflorescence can accumulate and deteriorate the surface minerals, resulting in voids and unattractive finishes. Surface Buff technicians can delicately remove and treat efflorescence. While we cannot guarantee that it will not reoccur, it typically diminishes with each treatment.