What Can We Tell from This Photo? (Case Study 16)
The feature photograph was taken of applique shingles. Applique shingles provide a dimensional appearance by adding a second coating of asphalt and granules, called an applique, over some areas to give the shingle a thicker appearance. This photograph provides helpful information regarding the cause and history of the damage.
From this photo we observe the following:
The widespread granule loss is on the applique. This is a common wear pattern from the loosening of the granules on the second coating of asphalt. This condition does not reduce the function of the shingles, but changes the appearance of the roof covering.
The cracking in the surface of the shingles is also in the applique. This is commonly due to the extra coating of asphalt coating shrinking more than the asphalt coating and mat below.
The spots in approximately the same location on the shingle strips is not from a sudden damage by hail, foot traffic, etc., but is due to a manufacturing defect. Some type of spot contamination on the roller caused the granules to not adhere as well at these spots. When exposed to the heat of the sun and roof runoff from rain, the granules loosened and dislodged.