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Collar Ties: Keeping Your Roof Together
When wind pushes on one side of your roof and pulls on the other, collar ties hold the rafters together. See how proper sizing prevents roof failure in Keys hurricanes.
Collar Tie Specs
The Triangle That Holds Your Roof
Your roof works because triangles are strong. The two rafters and the ceiling joist (or rafter tie) at the bottom form a triangle that cannot collapse without breaking something. But what happens at the top near the ridge?
Collar ties create a second, smaller triangle in the upper part of the roof. During a hurricane, wind can push hard on one side of the roof while creating suction on the other side. This uneven force tries to twist the roof and separate the rafters at the ridge. Collar ties resist this by holding the opposing rafters together.
Why Position Matters
Collar ties must be in the upper third of the rafter span to work properly. If you install them too low, they act more like a ceiling joist and less like a collar tie. The higher position creates a smaller triangle that is more effective at preventing ridge separation during wind events.
In Monroe County, collar ties typically need to be at least 1x6 lumber, and often 2x4 or 2x6 for longer spans or higher wind loads. The connections are critical - at least three 10d nails at each end, or metal connectors rated for the tension load. A collar tie that pulls loose is the same as no collar tie at all.
For cathedral ceilings where you cannot use rafter ties at the bottom, properly sized ridge beams and collar ties become even more important. The engineer must verify that the collar ties can handle all the lateral thrust that would normally go to the rafter ties.
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Properly sized collar ties for your roof span and Monroe County wind loads
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