Blistering in asphalt composition shingles is defined as collections of moisture “pockets” within the asphalt that vaporize from thermal heating, producing a balloon-like form within the asphalt. Blisters tend to grow, elevating the granule surfaces, eventually rupturing, causing granule displacement.
Vertical, Diagonal, and Horizontal stress fractures occur when the reinforcement mat cannot withstand the movement within the thermal sealed shingles creating “splits” or fractures in the shingle resulting in possible water intrusions.
Examples of Horizontal Stress Fractures
Examples of Vertical Stress Fractures