By Bud Coburn
- Pinched between the fingers, efflorescence will turn into a powder, while mold will not.
- Efflorescence forms on inorganic building materials, while mold forms on organic substances. However, it is possible for mold to consume dirt on brick or cement.
- Efflorescence will dissolve in water, while mold will not.
- Efflorescence is almost always white, yellow or brown, while mold can be any color imaginable. If the substance in question is purple, pink or black, it is not efflorescence.
- fungi that rot wood;
- water damage to sheetrock;
- reduced effectiveness of insulation.
Inspectors should note the presence of efflorescence in their inspection reports because it generally occurs where there is excess moisture, a condition that also encourages the growth of mold. An exception can be made during the first few years of a building’s construction when efflorescence will appear as a result of moisture locked within the masonry in a process called “new building bloom.” This moisture comes from water added during the manufacturing or mixing process that will undoubtedly contribute to efflorescence. This type of efflorescence will appear all over the masonry material and will continue to accumulate until the initial water supply is exhausted, which can take up to a year. Efflorescence that appears locally and after the “new building bloom” is over is a symptom of excess moisture that can be problematic. The source of this moisture should be determined and corrected.
Prevention and Removal of Efflorescence
- An impregnating hydrophobic sealant can be applied to a surface to prevent the intrusion of water. It will also prevent water from traveling to the surface from within. In cold climates, this sealant can cause material to break during freeze/thaw cycles.
- During home construction, bricks left out overnight should be kept on pallets and be covered. Moisture from damp soil and rain can be absorbed into the brick.
- Pressurized water can sometimes be used to remove or dissolve efflorescence.
- An acid, such as diluted muriatic acid, can be used to dissolve efflorescence. Water should be applied first so that the acid does not discolor the brick itself. Following application, baking soda can be used to neutralize the acid and prevent any additional damage to the masonry. Muriatic acid is toxic, and contact with skin or eyes should be avoided.
- A strong brush can be used.
Note: The use of water to remove efflorescence may result in the re-absorption of crystals into the host material, from which they may later reappear as more efflorescence. It is advisable that if water is used in the removal process that it is dried off very quickly.