Efflorescence: Unsightly deposits
Photo credit: Tim Carter | These salt crystals appeared when water evaporated from a puddle on a concrete floor. (2013)
White deposits on the exterior of a home are almost certainly efflorescence. They're just salt crystals that are left behind when water evaporates from the masonry surfaces around a house.
The problem starts inside a chimney, retaining and foundation walls, and patio paving stones. The source of the problem also can be what's behind these materials. Soil, brick, mortar, concrete block, concrete...
