How Efflorescence FormsThe earth contains natural salts that are present in the raw materials that make up masonry products, such as concrete, asphalt and stucco. These salts remain trapped within masonry in solid form until they are dissolved into water, which usually makes its way into the material through small pores. Water can originate from rain, sprinklers, household leaks, or any number of other places. Cold, dry air will draw this liquid back out of the material where it evaporates, depositing the salt as a white crystalline growth on the surface. Efflorescence typically forms during cold, dry weather shortly after it has rained and moisture has entered the masonry. It can occur year-round, but it is most likely to form during the winter due to low temperatures.
Identifying EfflorescenceAs with mold, the appearance of efflorescence varies greatly. It can be powdery, it can have sharp edges and be easy to spot, or it can have indistinct edges. It can cover a large area as a fine dust, or form large individual crystals. Its appearance depends partly on the type of salt from which it is composed, but humidity also plays a role in this determination. In exceptionally dry climates, water can evaporate before it even reaches the surface, in which case the salt will accumulate unseen beneath the surface. In humid conditions like here in Texas, moisture may take a long time to evaporate, allowing the slow growth of “whispers” projecting from the surface. We already know how to distinguish mold (pictured at right) from efflorescence, but it is possible for homeowners to confuse the two. The expense of a mold test can be avoided if the substance in question can be identified as efflorescence. Here are a few tips that we can offer our clients so that they understand the differences:
- 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.
Prevention and Efflorescence Removal
- 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.
- We are providing this as informative information only. We strongly advise hiring us, or another professional to perform the removal of efflorescence due to the chemicals that may be needed in the removal process.
- Pressurized water can sometimes be used to remove or dissolve efflorescence. Hot water pressure washing will do the trick on a lot of cases.
- 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.