What helps prevent rafter spread during construction?

Collar ties play a crucial role in structural stability during construction by preventing rafter spread, which can occur when the roof is subjected to load. Rafter spread is the outward movement of the rafters at the ridge, which can lead to structural failure if not properly managed. Collar ties are horizontal members that connect opposing rafters near the upper third of the roof. By tying the rafters together, collar ties help maintain the shape of the roof structure and resist the forces that would otherwise push the rafters apart.

In contrast, while brace reinforcement can provide additional support and strengthen the structure, it primarily focuses on lateral stability rather than directly preventing rafter spread. Sheathing installation adds rigidity to the roof system and contributes to load distribution, but it does not function in the same manner as collar ties with regard to preventing rafter movement. Ventilation headers serve to provide adequate airflow in the attic space but do not play a role in the structural integrity of the rafter system. Therefore, collar ties are specifically designed to address and mitigate the risk of rafter spread during construction.