Shingle Granules and Your Gutters

The most popular roofing material for homes throughout Canada and the US is asphalt shingles because they are relatively easy to install as opposed to other types of roof tiles such as slate, stone, or ceramic. However, when these granules land in the gutters, it can be a sign of trouble for your roof. But should you also be concerned about the gutters if you discover granule build-up in the gutter system?

Composition of Asphalt Shingles

Asphalt shingles start with a mat core (organic or fiberglass) that is coated with layers of asphalt. The final layer is then encrusted with pulverized minerals. Once the granules are embedded into the surface, this top layer protects the shingle from the elements, specifically from UV rays. To provide additional stability and protection, the shingles of a properly installed roof overlap one another.

While the appearance of asphalt shingles might look similar, different manufacturers use different quality of materials and manufacturing techniques that impact a roof’s longevity and durability. It’s important to note that even a newly installed roof can shed a few granules after intense rain or wind activity. As the roof ages, asphalt shingle granules in the gutters can be an indication of normal wear-and-tear.

When You Should Worry about Shingle Sediment

Because the top layer of each asphalt shingle has a lot of tiny embedded minerals or pieces, as mentioned above, it’s normal for homeowners to find shingles granules in the gutters after inspecting or cleaning them. When it becomes a cause for concern for the gutter system is if the shingle sediment has accumulated to a thickness of 0.5 inches to 2 inches. Combine the amount of shingle sediment with poorly maintained gutters, a black sludge can form as leaves, twigs, etc. breakdown and mix with rainwater. If airborne seed pods land into a gutter channel lined with sludge or silt, plant life can grow, even small trees.

What Shingles Granules Tell You about Gutters

Gutter cleaning and regularly maintaining the gutters reduces the occurrence of common gutter problems. Any kind of debris including singles granules slows down the flow of rainwater through the gutter channels. When not a sign of a failing roof, shingle sediment buildup might be an indication that the gutters have become misaligned or the gutter system isn’t being properly maintained.

Do I Need a New Roof if I Find Granules in the Gutters?

The most likely reason for roof shingle granules is poor gutter cleaning habits. Depending on how many trees are on your property and their proximity to the house, gutter professionals recommend that the gutters and downspouts be cleaned a minimum of twice a year, middle of spring and the end of fall.

However, if the sediment for shingles granules sit in the gutter channel up to 2 inches deep and can be removed easily with a gutter scoop, it might be time to consult a roof contractor. In addition to shingle granules buildup in the gutter system, look for:

  • Bald spots on roof tiles
  • Missing or loose shingles
  • A section of shingles that are damp or water-stained
  • Sagging sections
  • Rusted flashings
  • Soil erosion
  • Visible damage such as holes or cracked shingles
  • Age of the roof – 20 years or older