If this is not successful, repeat and very gently scrub the affected area with a soft bristle brush in order not to damage or dislodge the mineral granules
that protect the shingles from the sun's rays.
Experts say the mold or fungus that develops on some roofs can cause premature loss of the mineral granules
that protect asphalt shingles.
Because the base components of shingles, including asphalt, mineral granules
and fiber, are so similar to asphalt paving materials, ground shingles can be quite easily incorporated into hot-mix asphalt and other parching materials.
Signs of a weathered roof are excessive loss of protective mineral granules and cracked, curled or missing shingles.
Organic mat is saturated and coated with asphalt and then surfaced with ceramic-coated opaque mineral granules. The saturating process is not necessary for fiber glass-based asphalt shingles, which require only a coating asphalt.
Organic shingles consist of it wood-fiber base that is saturated with asphalt and coated with colored mineral granules. To fight fungus growth in warm, wet climates, they are available with special algicide granules.
Fiberglass shingles consist of a fiberglass mat, top-and-bottom layers of asphalt, and mineral granules. Like organics, they are available with algicide granules.
First, they cover the asphalt with hard mineral granules
to block the UV waves (and make our roofs colorful).