Gambrel Roof Collar Ties

I can now analyze the whole roof system as a simple three hinged arch.

Gambrel roof collar ties.

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. Using the gussets eliminates the need for the collar tie. The collar ties are used to strengthen the roof rafters to prevent them from buckling or sagging under the weight of the roof. 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.

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. Collar tie is a colloquial term for collar beam. The owner plans on using an engineered ridge beam and tells me that such a beam will eliminate the need for collar ties. The 2015 international residential code does not require collar ties or collar beams.

A gambrel style shed roof offers the most storage space in the attic when compared to a gable or saltbox style shed roof. Like rafter ties collar ties are horizontal members that tie the rafters. A friend has decided to put a gambrel roof on a 20 40 barn and has asked me to help in the framing. In this case the collars.

In high wind areas uplift can tear a roof off of a house if it s not properly attached. There are some exceptions however when collar ties might be useful even in a conventional attic roof. The guidelines i am about to explain for you outline the steps i use when i am designing my gambrel shed plans barn shed plans and small barn plans. I ve never framed a roof before but when i asked for details i didn t see collar ties in his drawing.

Compared with the traditional gambrel frame this method removes almost all of the complex analysis.