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Is it time for a new roof?
A sign of the normal aging process may be the development of surface cracks. The stresses created by thermal shock and the movement of the roof deck also increase the likelihood of surface cracking.
Curling: As the asphalt hardens over time, the granules which were once securely embedded begin to break away. Occasionally you may have seen the colored granules in your gutters. Also, as this hardening advances, the asphalt layers begin to shrink. As the asphalt layer shrinks, it is being countered by the shingle reinforcement, which resists shrinking. As a result, the edges of the shingle may begin to curl over time. In addition, organic shingles may exhibit signs of curling which might be considered excessive, however, this is not a manufacturing defect and would be considered part of the normal weathering process of organic shingles. During the course of natural weathering, small bubble-like raised areas known as blisters may appear on the surface of the shingles. The blisters may be small and pea-sized or as large as a quarter. The blisters may be open, exposing the asphalt, or closed. Blisters frequently result when minimum ventilation requirements are not met.
Staining: Finally, over a period of time, shingles may develop dark brown or black streaks that are sometimes mistaken for soot, dirt, moss or tree droppings. In actuality, this discoloration may be caused by algae growth. Although most roofing systems are susceptible to algae discoloration, it is most readily visible on white or light-colored shingles. |
Surface Cracking:
Blisters:

