North Carolina Building Contractor License Practice Exam

What is the maximum spacing for rafter ties (collar ties) on center?

1. 3 feet

2. 1/4 the depth of the rafter

3. 2 feet

4. 4 feet

The correct answer is: 1/4 the depth of the rafter

The correct answer is based on building codes that address the maximum spacing for rafter ties, also known as collar ties. The requirement that rafter ties should be spaced at a maximum of one-fourth the depth of the rafter is essential for maintaining structural integrity and supporting the roof system properly. When rafters are used, they help to hold up the roof. Collar ties are installed to prevent the rafters from spreading at the eaves due to the weight of snow and other loads. By specifying that the maximum spacing between these ties is one-fourth the depth of the rafter, it ensures that the ties can effectively resist lateral load and provide adequate bracing. For example, if a rafter is 12 inches deep, the maximum spacing of the rafter ties could be 3 inches apart to provide sufficient support. Understanding this spacing requirement not only helps in ensuring compliance with building codes but also plays a crucial role in the safety and durability of the building structure. Proper spacing is critical in preventing structural failures that can arise from inadequate bracing.