Some embodiments relate to asphalt shingle waste coatings in roofing shingles of roofing systems. A roofing system comprises a plurality of roofing shingles. The plurality of roofing shingles, when installed on a roof substrate, comprises exposed surfaces and unexposed surfaces. The plurality of roofing shingles comprises asphalt shingle waste coatings on or only on at least one of the unexposed surfaces. The plurality of roofing shingles comprises asphalt coatings on or only on at least one of the exposed surfaces.