Answers · Is something wrong?
Should I worry about granules in the gutter?
The short answer
A small amount is normal, especially in the first months after a new roof and after a hailstorm. What matters is whether the roof shows bare patches where the darker mat is exposed. Granules in the gutter with no visible bare areas is shedding; bare areas is wear.
What granules do
They are the roof's sunscreen. The mineral surface protects the asphalt beneath from ultraviolet light, and once it is gone the asphalt dries, hardens and cracks. That is the actual failure mechanism of an asphalt roof, and it is why granule loss is the signal rather than a cosmetic complaint.
When it means something
- A sudden large quantity after a hailstorm, which is evidence for a claim and should be photographed.
- Concentrated loss below one slope or one area, which points at a local cause.
- Visible bare or shiny patches on the roof, seen from the ground with a zoom lens.
- Loss that continues heavily years into a roof's life, rather than tapering after the first season.
Also asked
- Does pressure washing a roof remove granules?
- Yes, and that is the main reason not to do it. High-pressure washing strips the mineral surface and takes years off an asphalt roof. Treatments for moss and algae are applied at low pressure or not sprayed at all.
General information about roofs and about hiring, not advice about your building. Roofing contractor licensing, permits, insurance practice and deductible rules are set state by state and province by province across the United States and Canada, so your own authority is the current answer.