A coloured grain of stone
A granule is a fragment of rock covered with a colour coating. At the factory, it is pressed into the still-hot asphalt. The granule shields the asphalt from the sun, which would dry it quickly if it were bare. It also gives the roof its colour and texture.
A shingle that has lost its granules is exposed to the sun. Sand in the gutters is one of the shingle problems to keep an eye on.
Three situations, three readings
The roof has just been redone. The manufacturer puts on more granules than the asphalt holds. The surplus, simply resting on the surface, comes off with handling, installation, then the first showers. For a few months, it is normal to find some in the gutters and at the foot of the downspouts. On the roof, the colour stays even and the shingles well covered. The phenomenon fades on its own.
The roof is getting old. Dry asphalt grips its granules less well. The loss starts again, slowly at first, then faster. Three clues warrant having us look at the roof:
- there is more sand in the gutters at each cleaning
- smooth areas, darker than the rest or shiny, appear on the slopes
- in the same spots, the shingles are cracked, stiff or deformed
The loss is concentrated in one spot. Age is then not the cause, and there is an explanation to find.
- A downspout from an upper roof empties onto the slope. The water constantly rinses the same strip.
- A branch sweeps the shingles when it is windy.
- Hail has struck. It leaves small round marks, scattered at random, where the granules are gone.
These cases are often settled without touching the rest of the roof. We extend the downspout to the lower gutter or replace the affected shingles. For the branch, a tree trimmer is needed.
Keeping count from one year to the next
Gutters keep a record of the granules. The loss can be followed from year to year, without leaving the ground.
- The day a professional empties your gutters, have them photograph what they find before removing it.
- Between two cleanings, glance at the deposit left at the bottom of the downspouts.
- On a clear day, examine each slope from the yard with binoculars.
- Put the photos side by side each year. A deposit that does not change is a good sign. A deposit that grows is a warning.
Do not climb a ladder to look at the bottom of a gutter. The professional's photo is enough.
Frequently asked questions
At what amount should I worry?
No figure serves as a threshold. Look instead at which way the amount is moving and what the shingles look like. A bit of sand with an evenly coloured roof is fine. A gutter lined with sand under a slope marked with bare areas means it is time to have us look at the roof.
Can a bare shingle be re-coated?
No, a bare shingle cannot be re-coated in a lasting way. A granule holds when the factory presses it into hot asphalt. If an accident stripped a few shingles, we replace them. If wear stripped the roof, it needs to be redone.
Does my warranty apply to granule loss?
It all depends on the cause and what the warranty text says. Normal wear is often excluded. If a recent roof is losing a lot of granules over a large area, notify the roofer and the manufacturer, with photos and the invoice.