Ace the Illinois Roofing Practice Exam 2025 – Nail It and Soar to New Heights!

The correct answer is that drainage should occur within 48 hours following a rainfall. This timeframe is crucial for maintaining the integrity of a low slope roof system. Effective drainage helps to prevent water damage, mold growth, and structural issues that can be caused by standing water.

While it is ideal for drainage to occur even sooner, having a standard of 48 hours ensures that there is a clear expectation for roof performance under typical conditions. Hurricane and extreme weather events may require different assessments, but for normal rainfall, this timeframe helps protect the roof and its underlying structures.

In this context, the other options present a range that doesn't align with best practices for roofing systems. 24 hours may be too short to account for all conditions, and 72 hours may be excessively lenient, allowing water to sit too long. No specified timing would not provide a clear standard for performance, leading to potential complications in managing water accumulation on low slope roofs.