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Constructing Roof Rafters
In traditional roof framing the main structure of all roofs are the
rafters.
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Forming the rafters can be very complex in some
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One end of the rafter is notched out and sits on top of
the wall plate. From there it is angled upwards to meet with
another rafter or the ridge board. The spacing and size of the
material of the rafters is dependent on the design and load
requirements. They can be installed as close as every 16-inches to
as far as 48-inches. The exposed part of the rafter or the
overhang creates the eave of the structure. The eaves help to
protect the exterior walls, windows and doors from roof water runoff and
help to distance water, ice and snow from the building's foundation.
As you can see from the drawing below in order to install the rafters
compound angle cuts are required on many of the rafter boards.
This is very time consuming, and requires a lot of time in measuring
each board. This is one of the reasons for the creation of the
fabricated roof truss.
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Common Rafter:
The common
rafter is always at right angles to both the wall plate and the roof ridge
rafter.
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Hip Rafter:
The rafter that
comes from the corner of the wall plate and extends to the roof ridge.
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Jack Rafters:
There are three different types of jack rafters:
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Cripple:
A rafter that runs between a hip and valley rafter. It
has no contact with either the ridge rafter or the wall plate.
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Hip:
A rafter that runs between a wall plate and a hip rafter.
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Valley: A rafter that runs between a valley rafter and a ridge rafter.
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Valley Rafter:
The rafter that
goes from the wall plate to the ridge rafter between the intersection of two
roof segments. As in a cross gable or hip roof.
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