Efflorescence

Efflorescence -  A white, chalky, crystalline residue on walls.

Efflorescence is a sign that water or moisture was absorbed into the masonry, cement or concrete at one time. The moisture in the masonry walls and floor, has dissolved some of the water-soluble ingredients like lime and calcium. When these minerals dry out, crystals form, leaving efflorescence

Causes and Remedies for Efflorescence

There can be a number of causes for this type problem. Some of the would be

High Humidity – If high humidity is the cause of your problem, the white residue will usually be uniform over a large broad area. Often times, you can see staining up to a certain height on the wall and it occurs at a generally consistent height. The reason high humidity can cause efflorescence, is because high humidity leads to condensation forming on the masonry surfaces. Condensation causes beads of moisture to form on the cool surfaces and is absorbed into the porous cement.

Wall Cracks and/or Failed Parging – Once you get a crack in your masonry walls, the parging that keeps out water, fails. Because the masonry is porous, it will wick in water or moisture. When the moisture dries out, the minerals and other water soluble ingredients that leached out, begin to crystallize. This looks like white powdery stains on the walls and is called efflorescence.

To Remove Efflorescence – Wear a dust mask and wire brush all the loose material off. Using a chemical etching solution will also be helpful. The surfaces should then be primed before applying a sealer. Read the product instructions to make sure all the materials you are using are compatible.

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