Colour Fading of Roof Shingles

Technical Bulletin #19

Current as of May 2018

Shingle colour fading is typically very gradual and very slight.  It can be noticed as:

  • a change in the colour or,
  • a loss of “gloss” or lustre.

This phenomenon may start after the first few years of exposure and can continue over time.

The main reason is that asphalt shingles are covered with coloured granules to protect the asphalt from UV radiation, to provide the user with colour choices, and to provide a degree of fire resistance. The granules are generally of a natural stone, coated with colouring pigments. Although the pigments are fused to the granule surface by a ceramic process, as with other products, some of the pigments used can still be affected by UV radiation, which can make the colour to fade gradually.

Other factors which can affect the rate of colour change are:

  1. Orientation of the roof (south exposures are more severe than north exposures),
  2. Shade or obstacles,
  3. Biological effects such as mold, algae, etc.,
  4. Environmental factors such as acid rain.

Though the granule colour may fade, this will have no impact on the protection which the granules provide to the asphalt.

The information contained in this bulletin is for general education and is not intended to replace advice from a qualified contractor or direction on usage/installation from the manufacturer. Consumers should be aware of the safety hazards associated with work on roofs and, before doing so themselves, should consider following CASMA s advice of using qualified contractors. This bulletin may be reproduced with permission on condition that it be reproduced in whole, unedited, with attribution of copyright to CASMA.