Gambrel Roof Collar Ties

Collar tie is a colloquial term for collar beam.

Gambrel roof collar ties.

The 2015 international residential code does not require collar ties or collar beams. Like rafter ties collar ties are horizontal members that tie the rafters. Collar ties are connections between opposing rafters at the upper one third of the roof frame area just below the ridge and they are required at a 48 4 maximum spacing which is every other rafter of a 24 on center spacing and every third rafter with 16 on center spacing. A gambrel style shed roof offers the most storage space in the attic when compared to a gable or saltbox style shed roof.

I can now analyze the whole roof system as a simple three hinged arch. I ve never framed a roof before but when i asked for details i didn t see collar ties in his drawing. However in those situations when they are specified collar ties or ridge straps are usually installed in the upper third of the roof between opposing rafters. Compared with the traditional gambrel frame this method removes almost all of the complex analysis.

For example very long rafters in a relatively steeply pitched roof slopes above 6 12 for instance may benefit from a stabilizing effect if adequately connected collar ties are installed on every rafter pair. A friend has decided to put a gambrel roof on a 20 40 barn and has asked me to help in the framing. The owner plans on using an engineered ridge beam and tells me that such a beam will eliminate the need for collar ties. Using the gussets eliminates the need for the collar tie.

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. In this case the collars. 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. There are some exceptions however when collar ties might be useful even in a conventional attic roof.

In high wind areas uplift can tear a roof off of a house if it s not properly attached.