Roof Rafter Collar Ties

A tension tie in the upper third of opposing gable rafters that is intended to resist rafter separation from the ridge because of wind or unbalanced roof loads.

Roof rafter collar ties.

A collar tie is a horizontal roof rafter compression connector that is located in the uppermost third of the span of a pair of opposed sloped or gable roof rafters. This is especially important if the home is in the northern climates where snow accumulates on roofs or if there are multiple layers of roofing materials. By upper third here we mean one third of the length of the rafter from ridge to top plate. Collar ties may take up space in the attic of your home but they are there for a reason.

In this how it works article managing editor debra judge silber explains the role of collar and rafter ties in the framing of a roof. Collar ties are necessary to prevent separation of the roof at the ridge due to wind uplift. Rafter ties resist the forces caused by gravity loads that would otherwise cause the roof to pancake and push out the sidewalls. Collar ties provide additional structural support for wood framed roofs that bear the weight of clay or concrete roofing tiles.

The collar ties are used to strengthen the roof rafters to prevent them from buckling or sagging under the weight of the roof.