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.
Roof construction collar ties.
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.
Definition of collar tie in roof framing.
The 2015 international residential code does not require collar ties or collar beams.
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.
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.
Sagging rafters leaning walls collapsing roofs how defects in roof framing or damage to roof connections or structural members lead to building damage.
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.
The collar ties can be wrapped with drywall or a higher grade of lumber can be used and left exposed.
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.
The collar ties are used to strengthen the roof rafters to prevent them from buckling or sagging under the weight of the roof.
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.
A collar tie is a horizontal member between two rafters and is very common in domestic roof construction.
They still tie the rafters together but they no longer form the low flat barrier that ceiling joists do.
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.
By upper third here we mean one third of the length of the rafter from ridge to top plate.
Often collar ties are structural members but they may be used simply to frame a ceiling.
Collar ties may take up space in the attic of your home but they are there for a reason.
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.
In a frame like this the remaining collar ties are often doubled up putting one 2x on each side of the rafter.
This balances the construction and makes it look beefier.
