Roof Construction Collar Ties

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

Roof construction collar ties.

The much maligned collar tie. Sagging rafters leaning walls collapsing roofs how defects in roof framing or damage to roof connections or structural members lead to building damage. By upper third here we mean one third of the length of the rafter from ridge to top plate. A collar tie is a tension tie in the upper third of opposing gable rafters that is intended to resist rafter separation from the ridge beam during periods of unbalanced loads such as that caused by wind uplift or unbalanced roof loads from snow.

They still tie the rafters together but they no longer form the low flat barrier that ceiling joists do. In collar tie roof the horizontal tie is raised up from the feet of the rafters to the almost middle of the rafters. First referenced in the irc in 2006 collar ties had been required long before that in the southern standard building code and in the high wind provisions of the uniform building code. We include sketches of collar ties rafter ties and structural ridge beams as well as illustrations of collapsing and collapsed structures where these roof rafter ties were lost or omitted.

Often collar ties are structural members but they may be used simply to frame a ceiling. A collar tie is a horizontal member between two rafters and is very common in domestic roof construction. 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.

The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. Collar ties collar ties are horizontal framing members that are essentially ceiling joists that have been moved upward to span the distance between the rafters higher than the top of the walls. In a frame like this the remaining collar ties are often doubled up putting one 2x on each side of the rafter.

The last roof framing member to discuss is the collar tie also called a collar beam. Collar ties are necessary to prevent separation of the roof at the ridge due to wind uplift. The collar ties can be wrapped with drywall or a higher grade of lumber can be used and left exposed. Definition of collar tie in roof framing.

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.