RAFTER AND ROOF COMPONENT PARTS

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Presentation 19

• RAFTER AND ROOF COMPONENT PARTS

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Gable Roof
A gable roof is the more common roof style.
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Gable Roof
These rafters are referred to as COMMON rafters.
A symmetrical triangular shape.
Made with gable rafters, which are all the same.
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Roof Framing Terms
Span is usually the width of the building.
Terms relating to roof framing include
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Roof Framing Terms
Run is the horizontal distance under a rafter.
Rise is the total increase in rafter elevation.
In this case it is one-half the span.
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Rafter Parts
Ridge
Rafter
Rafter Tail
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Ridge Cut
Ridge Plumb Line
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Birds Mouth and Tail
Birds Mouth or Seat Cut
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Birds Mouth and Tail
Birds Mouth Plumb Line
Tail or Fascia Plumb Line
Birds Mouth Level Line
Tail or Soffit Level Line
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Projection vs. Overhang
Always sloping
Overhang
Projection
Always horizontal
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Rafter Parts
Rafter or Line Length
- from the ridge plumb line to birds mouth plumb
line.
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Rafter Parts
Unit Rise
Unit Triangle
Has three parts just like the house.
Found on the plans and similar to Total Rise.
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Rafter Parts
Unit Run
Unit Length
Equal to 12? and similar to Total Run
Similar to Line Length
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Conclusions

• Gable rafters are called common rafters.
• Rafters have many component names.
• Rise, run, and length are terms used to define
  parts of a rafter.
• Unit triangle is similar to the house triangle.