40 Hour Property and Building Inspection Practice Test

Should the size of a purlin be the same as the ridge?

1. Yes, it should

2. No, it should not

3. Only if specified

4. Depends on local codes

The correct answer is: No, it should not

The size of a purlin should not necessarily be the same as the ridge. Purlins are horizontal members that support roof decking or sheathing and are positioned perpendicular to the roof's slope. Their primary function is to transfer loads from the roof to the structural framework below. The ridge, on the other hand, is the horizontal line at the top of the roof where two sloping roof sections meet. It serves as a critical structural element, often designed to handle different load requirements compared to purlins due to its unique position and the way it distributes stresses from the roof's surface. Since purlins and ridges serve distinct functions and are under different types of stress and load, their sizes and dimensions will likely differ. Proper design and sizing will depend on various factors, including the specific structural requirements, load conditions, materials used, and engineering principles applied to the roof system. Thus, it is common practice for these two components to have different sizes based on their functional needs in the overall structure.