Those small, sand-like grains collecting at the bottom of your gutters or washing out of a downspout are granules from your asphalt shingles. They're the roof's sunscreen. Each shingle is coated in mineral granules that shield the asphalt underneath from UV light. In Albuquerque, where the sun is strong and the altitude is high, that protection matters more than in most places.

Why Shingles Shed Granules

  • New-roof shedding. A new roof often releases loose, extra granules for the first several months. This is normal and usually tapers off.
  • Normal aging. As shingles age, the asphalt that holds granules in place dries out and releases them slowly. Our guide to altitude and UV aging explains why this happens faster here.
  • Hail. Hailstones can knock granules loose in a concentrated area, leaving dark bruises where the asphalt is exposed.
  • Foot traffic and debris. Walking on the roof, dragged equipment, or branches rubbing the surface can scuff granules off.
  • Water flow. Valleys and the areas below downspouts that empty onto the roof lose granules faster because more water runs across them.

When Granule Loss Is a Problem

A light dusting in the gutters is not a reason to worry. These signs are:

  • Granules piling up in gutters after every rain, not just once
  • Smooth, dark or shiny patches on the shingles where the black asphalt shows through
  • A sudden increase in granules right after a hailstorm
  • Shingles that look noticeably lighter or patchy compared to other slopes of the same roof
  • Curling, cracking or brittle shingle edges alongside the granule loss

Why it matters: once the asphalt is exposed, UV breaks it down much faster. Bare spots tend to crack and eventually leak, so heavy granule loss usually means the roof is closer to the end of its life than its age suggests.

Granule Loss After Hail

If the granules showed up right after a storm, look for other hail signs before assuming it's just wear: dents in gutters, downspouts and metal vents, and dark circular marks on the shingles. Our hail damage visual guide shows what to look for. Storm damage may be covered by homeowners insurance, while normal wear usually isn't, so knowing which one you have matters before you call your insurer. See how to file a roof claim after a hailstorm.

How to Slow Granule Loss

You can't stop shingles from aging, but you can avoid speeding it up:

  • Never pressure-wash shingles. High-pressure water strips granules off in minutes.
  • Keep foot traffic off the roof. Every trip across the roof scuffs the surface, especially on hot afternoons when the asphalt is soft.
  • Trim branches that brush against the roof in the wind.
  • Fix attic ventilation. A hot attic bakes shingles from underneath. Our roof ventilation page explains how a balanced system helps.
  • Redirect downspouts from upper roofs so they don't empty straight onto the shingles below.

Granules on Other Roof Types

Granule loss is an asphalt shingle issue. Metal, tile and TPO roofs don't have granules, so grit in the gutters of those roofs usually comes from windblown dust, which Albuquerque's dust storms deliver in quantity. Some modified bitumen flat roofs do use a granulated cap sheet, and those can shed too.

What to Do Next

  1. Check from the ground. Use binoculars or photos from a phone to look for bare patches. There's no need to climb on the roof.
  2. Note when it started. A date helps separate storm damage from gradual aging.
  3. Get a documented inspection. A roofer can tell cosmetic shedding from functional damage and give you photos either way. Our Free Roof Report does exactly that.

If the roof is near the end of its life, compare your options on our repair vs. replacement page, or read the signs you need a new roof.