White Stains On Roof

The area can be cleaned.

White stains on roof.

Trees plant debris stains. White rust or white storage stain is one of the typical problems faced in galvanized coatings. Algae lichens and moss for example. It occurs as a white bulky powdery deposit that forms rapidly on the surface of the galvanized coating under particular environments.

Rust or chimney soot stains red or brown rust stains around chimneys is a common roof stain. The deposits found on different materials vary significantly in chemical composition and method of formation. Understanding efflorescence in this example defective roof flashing led to excessive moisture which in turn caused that ugly white powder on the grout joints and tile. The white stains shown on this wood shingle roof are in fact not a stain but an absence of lichens or moss.

White rust can cause substantial damage to the galvanized coating and is detrimental to its appearance. White stains on roof surfaces may be from wash down of pigments in paint on surfaces above the roof such as a gable end or dormer wall. In another situation the problem could be the result of moisture from the soil under a basement floor or wall and might require a vapor migration membrane instead. Metal salts washing down the roof surface from metal chimney flashing are often enough to kill of biological organisms that otherwise stain various roof surfaces.

White stains on slate roofs efflorescence or salt stains from rain water sometimes appear on slate shingles. Here are some clues to follow.