Granules in your gutters?
Granules are a shingle’s sunscreen. Finding them in gutters and downspouts means the asphalt underneath is starting to see the sun.
Illustration
What you’re seeing
- In the gutters: Sand-like grit collecting in gutters and at downspout outlets
- On the roof: Darker, smoother patches where the granule layer has thinned
- After storms: More granules than usual washed down after heavy rain or hail
What causes it
Sunlight and heat oxidize the asphalt that holds granules in place. As it dries and shrinks, granules loosen and wash off, exposing more asphalt to UV, which speeds up the cycle.
Illustration
Up close
Where granules are gone, the dark asphalt underneath is exposed to the sun. That bare, smoother surface is what to look for.
Can preservation help?
Usually a good candidate
Early to moderate granule loss on a sound roof is exactly what preservation is for: the SPS System bonds into the surface and encapsulates the granules that remain. Bare patches across most of the roof mean it has gone too far.
- Check the guttersA little grit is normal on new roofs; steady loss on an older roof is the signal
- Roof-life assessmentA dealer measures how much granule is left, slope by slope