What you are seeing
- Coarse grit like sand at the bottom of a downspout or in the gutter trough
- Dark patches on the roof where the surface looks smoother or shinier
- Grit washing onto a driveway or path after heavy rain
- Bare black areas visible on shingle faces from the ground
- A gritty line along the base of the wall under an overflowing gutter
Normal loss against loss that matters
| Pattern | What it usually means |
|---|---|
| A small quantity in the first months after installation | Normal loose surplus from manufacture and installation |
| Grit after a hail or heavy-impact event | Impact damage worth documenting and inspecting |
| Steady accumulation on a roof over about 15 years old | Ordinary end-of-life wear; start planning rather than reacting |
| Heavy loss concentrated below one roof plane | Localised cause — often the plane with the most sun or the most water flow |
| Bare black patches visible from the ground | The asphalt is exposed to ultraviolet light and will deteriorate faster from here |
Why it matters more than it looks
The granule layer is not decorative. It shields the asphalt from ultraviolet light, and once it is gone from an area the shingle beneath ages considerably faster than the rest of the roof. That is why granule loss tends to accelerate: the more exposed asphalt there is, the quicker the surrounding material follows.
It is also why granule loss is a timing signal rather than an emergency. A roof shedding granules is usually still shedding water. What it is telling you is that the useful life remaining is shorter than the calendar age might suggest, and that planning a replacement is better than waiting for the first leak to force one in February.
What to do now
Collect what accumulates over a few weeks rather than judging one handful, and photograph any bare patches from the ground. Note the roof's age if you know it, and whether there has been a hail or impact event recently, because damage and wear are handled very differently — including by an insurer.
If the roof is approaching the end of its expected life, this is the right moment to get a documented inspection and start budgeting. Planning a replacement outside the storm and late-season rush generally produces more considered proposals and better scheduling than trying to book during them.
Page last reviewed August 16, 2026.