What granules are for
Granules are small chips of stone with a colour coating, pressed into hot asphalt at the factory. They play two roles.
- Protecting the asphalt from the sun. Without them, the sun dries out the asphalt in a short time.
- Giving the roof its colour and texture.
A bare shingle has lost its sun shield.
On a new roof, it is normal
At the factory, more granules are applied than the asphalt can hold. The excess just sits on the surface. It comes off during shipping, installation, and then in the first rains.
After a roof replacement, expect to see coloured sand at the bottom of the downspouts and in the gutters for a few months. The shingles stay well covered and evenly coloured. The amount then drops off on its own.
On an aging roof, it is a warning
Over the years, the asphalt dries out and holds its granules less well. The loss starts again, slowly and then faster and faster. Granule loss is one of the easiest defects to follow. The gutters keep a record of it.
These signs deserve attention.
- the amount of granules in the gutters grows from one cleaning to the next
- smooth, black or shiny patches appear on the shingles
- the bare shingles are also dry, cracked or curling
Localized loss
Not all loss comes from age. When the loss is limited to one spot, look for a precise cause.
- Under a downspout that empties from a higher roof. The stream of water always washes the same strip.
- Under a branch that rubs the roof in the wind.
- After hail. Small round impacts, scattered at random, where the granules have popped off.
Localized loss can often be fixed without redoing the roof. We extend the downspout to the lower gutter or replace the damaged shingles, and an arborist trims the branch.
Following the trend
- When a professional cleans your gutters, ask for a photo of the amount of granules.
- In between, look at the coloured sand at the foot of the downspouts.
- Look at the slopes from the ground, with binoculars, on a clear day.
- Compare from one year to the next. A stable amount is reassuring, a rising amount is a warning.
Frequently asked questions
How many granules in the gutter is too many?
No amount of granules serves as a benchmark. The trend and the condition of the shingles count more. A handful of granules in a gutter, with well covered shingles, is no cause for concern. A gutter bottom full of sand, with black patches on the roof, should worry you.
Can granules be put back on a bare shingle?
No, granules cannot be put back on a bare shingle in a lasting way. Granules are pressed into hot asphalt at the factory. A shingle stripped by accident gets replaced. A roof stripped by age gets redone.
Is granule loss covered by the warranty?
Coverage of granule loss depends on the cause and the wording of the warranty. Normal wear is generally not covered. Abnormal, widespread loss on a recent roof should be reported to the contractor who installed it and to the manufacturer, with photos and your invoice.