Efflorescence

Robert moses secondary efflorescence 2

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K10 primary efflorescence

Efflorescence

Secondary efflorescence 1 of 2

Efflorescence is a term used in materials science and construction to describe a crystalline deposit of salts that can form when water is present in or on brick, concrete, stone, stucco, or other building surfaces. It appears as a white or greyish tint on the surface of materials and is especially visible on porous surfaces. Although efflorescence itself does not harm the structural integrity of a material, it can be an indicator of moisture issues that may need to be addressed to prevent damage.

Causes

Efflorescence occurs when water moving through a wall or other surface evaporates, leaving behind salt deposits on the surface. The source of the water can be groundwater, rainwater, or even humidity in the air. The salts are often naturally present in the materials used for construction, such as lime or gypsum in cement. When the water evaporates, it leaves the salt on the surface, creating the characteristic white bloom.

Prevention and Removal

Preventing efflorescence involves controlling water ingress into the material. This can be achieved through proper construction techniques, such as using water-resistant materials, applying sealants, and ensuring good drainage around structures. Once efflorescence has occurred, it can often be removed with a stiff brush and clean water. For more stubborn deposits, a diluted acid solution, such as vinegar, may be used, but care must be taken not to damage the material.

Impact

While primarily a cosmetic issue, efflorescence can indicate the presence of moisture within a structure. If left unchecked, this moisture can lead to more serious problems, such as the deterioration of the material or the development of mold. Therefore, it is important to address both the symptoms and the underlying causes of efflorescence.

See Also

• Concrete degradation
• Masonry
• Waterproofing