Some granules left after manufacturing detach during installation and early weathering. Finding them in a gutter does not, by itself, prove a defective roof
Malarkey technical bulletin: Asphalt Shingles and Granule Sloughing.
What this means for your roof
Some granules left after manufacturing detach during installation and early weathering. Finding them in a gutter does not, by itself, prove a defective roof. Malarkey distinguishes this normal shedding from exposed asphalt, unusual loss and damage following severe weather. Old gutters may also contain granules from the previous roof.
A useful question for your contractor
Ask for photographs of the shingle surface, not only the gutter, and for an inspection after damaging weather.
Ask for the answer to be tied to the actual roof condition and the exact product being installed. Keep the agreed repair or installation detail with your estimate and project photos.
Bulletin edition: August 2026. The date shown identifies the manufacturer document used for this summary.
Read Malarkey: Asphalt Shingles and Granule Sloughing
This homeowner summary explains the cited bulletin. The complete manufacturer document and current product instructions govern the installation details. A requirement for one manufacturer or product should not be transferred to another without checking.