Water dissolves salts in masonry and leaves crystals as it evaporates at the surface.
A crystalline white deposit is often efflorescence: salts carried to the surface by moving moisture.
Overflow concentrates roof runoff beside the wall, increasing splash, soil moisture and below-grade water pressure.
Roof runoff exits too close to the wall and repeatedly loads the same soil and foundation area.
Small pores draw ground moisture upward and toward drying surfaces, carrying dissolved salts.
Dry crystals and soft organic growth require very different interpretations.
Water-filled pores expand during freezing and progressively detach the surface.
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