Level up your aesthetic craftsmanship by broadcasting color-matched granules into side or end lap bleed out areas or liquid-applied flashing details. FlintRock™ Roofing Granules are tough, dense, non-porous, weather and UV resistant, ceramic-coated rock used as surfacing material for roofing purposes only, #11 grade. FlintRock is manufactured with true-blend colors (not just single granule colors) to match every CertainTeed low-slope membrane option and many popular shingles, for low-slope residential elements.