Which of the following is an indicator of inadequate ventilation in steep slope roofing?

The presence of stains and mold on steep slope roofing is a significant indicator of inadequate ventilation. When a roofing system lacks proper ventilation, moisture can become trapped in the attic or roof space. This trapped moisture creates an environment conducive to mold growth and the formation of stains on roofing materials.

Adequate ventilation is essential as it helps to regulate temperature and moisture levels, preventing damage caused by condensation and promoting a healthier indoor environment. As the warm, moist air rises, it needs a way to escape; otherwise, it condenses and contributes to mold growth and staining on materials. This is why stains and mold are strong indicators of ventilation issues in steep slope roofing systems.

In contrast, while ice formation can also result from inadequate ventilation, it is typically a symptom of other issues, such as heat loss through the roof, that leads to melting and refreezing at the eaves. Similarly, rusting is more indicative of moisture problems but not specifically tied to inadequate ventilation. Fastener back out may occur due to other mechanical or material failures rather than ventilation alone. Thus, the presence of stains and mold is a clear, direct sign of the need for improved ventilation.