Masonry products are one of the best investments homeowners can make for their home because of their longevity, endurance, and low-maintenance. However, one issue that can arise is efflorescence. It can initially be alarming; fortunately, it is a temporary issue that can be resolved and partially prevented with some context.
What is Efflorescence?
Efflorescence has been described as a residue, hazing, clouding, or chalkiness on a masonry product like concrete, brick, or stone. It is the remains of water-soluble salts or minerals left behind on the surface after the water has evaporated. It can present in a range of colors depending on the specific salts and minerals present. When the issue appears on the surface of the product, it is often assumed that the issue is coming from the product.
Typical Causes
For efflorescence to occur, first and foremost there must be salt or other water-soluble minerals present. The sources of those salts are not always clear. Occasionally, they are present in the product; but, much more commonly they are coming from a source in contact with the masonry product. These can be mortar ingredients, backing material, trim, or adjacent soil. Some sources are less obvious, like the water used to mix the mortar which can contain water softening salts or chlorine from being treated or salt used to melt ice and snow.
The next factor in efflorescence is water. There must be enough water exposure to dissolve the salts and carry them to the surface of the masonry product. Once the water evaporates, it leaves the salts behind. Water can come from several sources – rain, snow, condensation caused by temperature variance, leaks from plumbing, or poor drainage to name a few.
Treatment
Ideally, before any treatment is pursued, the source of the issues should be identified and resolved. Because of the myriad of possible causes, an experienced mason or the product manufacturer can help you determine the source of your specific issues.
With varying options and advice available, consult the manufacturer's recommendations to determine the ideal treatment for your product. There are several treatment agents on the market, but each masonry product has different qualities and can react to certain treatments unfavorably. The most common advice is to be patient and allow the efflorescence to run its course. Once all the salts and minerals have made their way to the surface, the problem will diminish. In the meantime, a sturdy bristled brush can help remove the salts as they reach the surface. However, do take care as to not remove any special finish on a product.
For more detailed information, we recommend the following sources:
The Brick Industry Association
Concrete Network
Masonry Institute