Prepare for the Illinois Roofing Exam with comprehensive quizzes. Utilize flashcards and multiple-choice questions, each with detailed hints and explanations. Start your journey to becoming a certified roofing professional in Illinois today!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.


A 45 degree angle represents what slope on a roof?

  1. 5:12

  2. 10:12

  3. 12:12

  4. 15:12

The correct answer is: 12:12

A 45-degree angle on a roof indicates a slope where the rise and run are equal. This means that for every 12 units (usually inches) of horizontal run, there is an equal vertical rise of 12 units. Thus, the slope is described as 12:12, which can also be expressed as a pitch of 1:1. This kind of slope is often referred to as a "flat" or "level" slope in roofing terminology, although in practice, it is quite steep. In practical applications, knowing that a 45-degree angle corresponds to a 12:12 slope is crucial for roofing calculations, drainage considerations, and ensuring that the roof can effectively shed water. The other options represent different slopes, specifically with varying relationships between rise and run that would not encapsulate the characteristics of a 45-degree angle.