Which of the following conditions is most likely to shorten the lifespan of asphalt shingles?

Incorrect installation is a significant factor that can drastically shorten the lifespan of asphalt shingles. When shingles are not installed per the manufacturer’s specifications, several harmful issues can arise. For instance, if shingles are laid too tightly, they might not have adequate room for expansion and contraction as temperatures fluctuate, leading to cracking or breaking. Additionally, improper alignment or nailing can create gaps that allow for water infiltration, resulting in leaks and accelerated deterioration. Ensuring that shingles are installed correctly is crucial not only for their performance but also for maintaining the warranty, as many warranties become void if installation mistakes occur.

Other conditions, while potentially harmful, do not directly impact the lifespan as severely as incorrect installation. For instance, color fading is primarily an aesthetic issue and does not affect the structural integrity of the shingles. Excessive moisture can lead to problems like mold or mildew, which might damage the underlayment or substrate, but these effects would typically take longer to manifest than issues from improper installation. Wind exposure can indeed cause damage, particularly in storms, but the effect on lifespan significantly hinges on the quality of installation. Correctly installed shingles will often perform better against wind and moisture than poorly installed ones, underscoring the importance of proper installation techniques.