Presentation 19:
RAFTER AND ROOF
COMPONENT PARTS
1
Gable Roof
A gable roof is the more
common roof style.
2
Gable Roof
A symmetrical
triangular shape.
These rafters are referred
to as COMMON rafters.
Made with gable rafters,
which are all the same.
3
Roof Framing Terms
Terms relating to roof
framing include …
Span is usually the
width of the building.
Span
4
Roof Framing Terms
Rise is the total increase
in rafter elevation.
Run is the horizontal
distance under a rafter.
Rise
Run
Span
In this case it is one-half the span.
5
Rafter Parts
Ridge
Rafter
Rafter Tail
6
Ridge Cut
Ridge Plumb Line
7
Bird’s Mouth and Tail
Bird’s Mouth or
Seat Cut
8
Bird’s Mouth and Tail
Bird’s Mouth
Plumb Line
Tail or Fascia
Plumb Line
Bird’s Mouth
Level Line
Tail or Soffit
Level Line
9
Projection vs. Overhang
Projection
Always horizontal
10
Rafter Parts
Rafter or Line Length
- from the ridge
plumb line to bird’s
mouth plumb line.
11
Rafter Parts
U
Unit Rise
Unit Triangle
Has three parts just like the house.
Total
Rise
Found on the plans and
similar to Total Rise.
12
Rafter Parts
Unit Run
Unit Length
U
Equal to 12″ and
similar to Total Run
Similar to
Line Length
Total
Run
13
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.
14