Which of the following is not a venting concern associated with flat roofs?

The correct answer identifies a scenario that does not inherently represent a venting concern associated with flat roofs. Ventilation is crucial for flat roofs to manage moisture and prevent issues like mold growth, material deterioration, and overall structural damage.

Having vents on all four exposures of the fascia could actually be beneficial. It would provide multiple avenues for air circulation, reducing the likelihood of moisture build-up and ensuring better airflow across the roof surface. This design can help create adequate ventilation, which is a fundamental aspect of maintaining a healthy roofing system.

In contrast, the other options highlight actual venting problems. For example, having no vents impedes airflow entirely, while vents obstructed by debris or structural elements can lead to similar negative outcomes. Additionally, vent areas totaling less than 1/150 of the roof area fails to provide sufficient air exchange, which is necessary for moisture control. Thus, the presence of vents all around the roof's fascia aligns with proper ventilation practices rather than being a concern.