Frosting: Salty looking discoloration, most visible on darker colors, sometimes mistaken for efflorescence.
Frosting probable causes: Usually forms in protected areas not receiving cleaning rains. Dark colors over paint or primer using excessive extender pigments. Mistaken for efflorescence.
Frosting solutions: Remove frosting with a wire brush on masonry and sanding on wood. Rinse thoroughly with a garden hose. For best and quickest results, use a power washer. Frosting often will bleed through new paint if an alkyd-based primer isn’t used.
Primers & exterior finishes: An alkyd primer is essential to avoid a recurrence of bleeding through the new finish coat only. Select a top quality exterior paint in the color and sheen of your choice.