Granules in Your Gutters: What They Mean

You cleaned the gutters and found what looks like coarse black sand. Or there is a small pile of it at the bottom of a downspout, next to the splash block.

Those are your shingles' granules, and finding them is the most common reason a homeowner starts worrying about the roof. Here is what they tell you, and what they don't.

What are shingle granules for?

The granules are the surface layer of the shingle. They give the roof its color, but that is not their job.

Their job is to take the sun. Asphalt breaks down in UV light, so the granules sit on top and absorb what would otherwise land on the asphalt underneath. They also add fire resistance and some weight.

When a shingle stops holding them, the asphalt underneath starts taking sun directly, and the aging speeds up from there.

Is some granule loss normal?

Yes. Two situations where finding granules means nothing is wrong:

A new roof. New shingles shed loose granules for the first few months. Those are leftovers from manufacturing that were never bonded in. It is expected and it stops.

After a big storm. Heavy rain and hail knock granules loose. A one-time pile after a storm is not the same as steady, ongoing loss.

What matters is not whether you found granules. It is whether you keep finding them.

What does ongoing granule loss mean?

Usually not that the shingle has worn out. It means the shingle has dried out.

An asphalt shingle is held together by oils, and those oils are what let it stay flexible and keep its granules. On the Gulf Coast, between the heat, the UV, the humidity and the salt air off the bay, those oils cook out of the shingle year after year.

A shingle that has lost its oils does two things at once:

1. It goes stiff. Your roof deck moves as it heats and cools. A shingle that cannot flex with it starts cracking at the edges and curling at the corners.
2. It loses its grip. The same dried-out asphalt that has gone brittle stops holding the granules in place, so they wash off into your gutters.

That is why granule loss and curling edges usually show up together. They are one problem with two symptoms.

What granule loss does not mean

It does not mean your roof is leaking. Granule loss and water getting in are separate things. Plenty of roofs shed granules for years without a drop coming inside.

It does not automatically mean you need a new roof. This is the assumption that costs people the most money. A roof that has dried out is not the same as a roof that has worn through, even though from the driveway they look identical.

It does not mean somebody did a bad job. This happens to well-installed roofs from good manufacturers. It is what this climate does to asphalt.

Why the difference matters

If the shingle has worn through, with cracks through the mat, fiberglass showing, or storm damage, the roof needs replacing and there is no way around it.

If the shingle is intact and has only gone stiff and dry, the oils can be put back. A treatment sprayed onto the roof soaks into the shingle and restores what the weather took out. The shingle flexes again and holds onto its granules again.

Nothing gets torn off. It is maintenance on the roof you already own, and it costs a fraction of a replacement.

The limits are real and we would rather you hear them from us. It does nothing for storm damage, it will not seal a leak, and there is a point where a shingle has lost too much to come back. It works on a roof that is aging, not one that is broken.

What should you do about it?

Don't panic, and don't ignore it. Granule loss is not an emergency, but it is a clock. Most people assume the right move is to wait until it gets worse.

It runs the other way. The treatment only works while the shingle is still sound. Once it has gone too far, or started leaking, that option is gone and replacement is all that is left. The window is while the roof looks tired, not once it looks finished.

Find out which roof you have. You cannot tell from the ground, and nobody should diagnose it over the phone. You want someone on the roof photographing your shingles and telling you plainly which kind you have.

Roof Reboot TX is based in Deer Park and works across La Porte, Pasadena, Baytown and the surrounding communities. We don't do repairs or replacements, so if your roof doesn't need treating there is nothing for us to sell you, and we will say so. The assessment is free and the photographs are yours either way.