Efflorescence on masonry walls occurs when moisture moves salts to the surface; which term describes this white deposit?

• A. Bleeding
• B. Hydration
• C. Efflorescence
• D. Seepage

Answer: (C)

Efflorescence is the white deposit you see on masonry when moisture moves soluble salts from the bricks, mortar, or surrounding materials to the surface. As the capillary water travels through the pores, it dissolves salts; when that moisture reaches the surface and evaporates, the dissolved salts crystallize and form a white, powdery crust. That crystallized residue is exactly what the term describes.

Bleeding is different: it’s water carrying fine cement paste oozing to the surface of fresh concrete, signaling excess water during placement. Hydration is the chemical reaction where cement reacts with water to form cementitious compounds that harden the material, not a surface salt deposit. Seepage refers to water seeping through walls or joints, causing dampness or staining, but without the characteristic salt crust. Thus, the white surface crust caused by salts carried by moisture fits the definition of efflorescence.