Every fourth pair of rafters should be installed with what type of tie?

The correct answer is that every fourth pair of rafters should be installed with a collar tie. Collar ties are important in roof construction because they help to prevent the rafters from spreading apart under load. They are typically installed horizontally between pairs of rafters near the peak of the roof. This placement is crucial as it helps to maintain the structural integrity of the roof system, especially in areas with significant wind or snow loads.

Collar ties are specifically designed to provide support and stability to the upper part of the roof structure. By securing every fourth pair of rafters with collar ties, builders ensure that there is adequate resistance to lateral forces that could impact the roof's performance during adverse weather conditions. This technique is part of sound construction practices aimed at enhancing the durability and safety of the building.