LEED AP Building Design and Construction (BD+C) Practice Exam

What roof slope is important concerning the heat island effect?

1. A slope of 1:12

2. A slope of 3:12

3. A slope of 2:12

4. A slope of 4:12

The correct answer is: A slope of 2:12

The correct answer relates to how the roof slope influences the potential for heat absorption and the subsequent heat island effect in urban areas. A roof slope of 2:12 is significant because it is moderate enough to allow for the implementation of various passive cooling strategies and the selection of reflective roofing materials. Roofs with very low slopes are more likely to accumulate water and absorb heat, leading to higher surface temperatures. A slope of 2:12 can facilitate better drainage to prevent heat retention from pooled water, which is crucial in minimizing the heat island effect. Additionally, the choice of materials plays a critical role; reflective surfaces are more effective on low to moderate slopes since they can be engineered to better reflect solar radiation and reduce the overall thermal mass of the roofing system. In discussing other options, steeper slopes like 3:12 and 4:12 might limit the effectiveness of certain cooling measures but can still utilize reflective materials. The very shallow slope of 1:12 is less effective for drainage and might retain heat more significantly. Overall, a 2:12 slope provides a balanced opportunity to mitigate heat absorption while allowing for effective water management and material choices.