Efflorescence is not harmful and is primarily just a cosmetic problem. But it is a symptom of ongoing moisture intrusion behind the porous surface of a masonry wall, which can eventually cause structural damage if allowed to continue. The powder that forms is salts that are wicked to the surface of the wall and then left behind by the evaporating water. 

    Efflorescence can be removed with a diluted acid wash. White vinegar can be used, and then rinsed off, for small residential areas. There are also proprietary foumulas available.  The water rinse should be used sparingly to avoid adding more moisture to the wall.

    Sometimes efflorescence occurs in the months immediately after when a masonry wall is laid, as the the material releases moisture to adjust to the climate. This initial discoloration may disappear within a few months.

    Also see our blog posts What are those powdery white areas on my brick walls? and What causes the surface of old bricks to erode away into sandy powder? and What causes raised white lines of residue on a block wall that are crusty and crumbling? and What does freeze damaged brick look like?

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To learn more about exterior walls and structures, see these other blog posts:

• What causes vertical cracks in fiber cement siding planks? 

• What is the difference between soil subsidence, heave, creep, and settlement? 

• How much ventilation is required for the under-floor crawl space of a home? 

• What causes stair-step cracks in a block or brick wall?

• What causes a horizontal crack in a block or brick wall? 

• How can I tell if a diagonal crack in drywall at the corner of a window or door indicates a structural problem?

• What are the pros and cons of concrete block versus wood frame construction?

• Should I buy a house with a crawl space? 

• Why is my stucco cracking?

• There's cracks running along the home's concrete tie beam. What's wrong? 

• What would cause long horizontal lines of brick mortar to fall out?

• How do I recognize serious structural problems in a house?

• What is engineered wood siding?

• Should I buy a house that has had foundation repair? 

• What is a "continuous load path”?

• Should I buy a house with asbestos siding?   

• How can I tell if cracks in the garage floor are a problem or not? 

• What do you look for when inspecting vinyl siding?

• Why is housewrap installed on exterior walls under the siding? 

• Why did so many concrete block homes collapse in Mexico Beach during Hurricane Michael? 

• How can I tell if the concrete block walls of my house have vertical steel and concrete reinforcement?

• Should I buy a house with structural problems? 

• What are those powdery white areas on my brick walls?

• What causes cracks in the walls and floors of a house?

• How can I tell if the exterior walls of a house are concrete block (CBS) or wood or brick?

• What are the common problems of different types of house foundations? 

• What are the warning signs of a dangerous deck?

• How can I tell whether my house foundation problems are caused by a sinkhole or expansive clay soil?

        Visit our EXTERIOR WALLS AND STRUCTURE page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.