1. Roof Design

2. Topics of Discussions Roof types Roof construction terms
Slope vs. Pitch
Roof terminology
Metal framing connectors
Roof ventilation

3. Basic Shapes Gable Roof Hip Roof Flat Roof Shed Roof Gambrel Roof
Mansard Roof
A-Frame Roof

4. Basic Shape Gable Roof Slopes in from two sides
Gable ends allow for attic venting

5. Basic Shape Hip Roof Slopes in from all four sides
No gable ends for vent attic

6. Basic Shape Flat Roof Requires a built-up roof
Slight slope of 1/4” to 12” helps drainage

7. Basic Shape Shed Roof 3/12 or more slope Can be shingled
Economical like flat roof

8. Basic Shape Two slopes from two sides Traditional “Barn” shape
Gambrel Roof
Two slopes from two sides
Traditional “Barn” shape
2nd story under roof

9. Basic Shape Mansard Roof Two slopes from two sides Top nearly flat
2nd story within the roof area

10. Basic Shape A-frame Roof Steep for snow country
Roof and ceiling same structure

11. Roof Construction Basic terms: slope/pitch--incline of roof
roof member terms--structure of roof
eave/cornice--detail showing wall to roof const
fascia--visible member attached to end of rafters
ridge--top of roof
sheathing--material covering the top of rafters
rafter/ceiling joist--structure framing of roof
soffit--underneath side of roof overhang
vents--in soffit, allows air circulation in attic

12. Slope Vs. Pitch Slope = Rise/Run Pitch = Rise/Span
Text book error (noted as pitch symbol)
Slope = Rise/Run
expressed as a ratio
always a base of 12
placed on dwg.
Slope symbol 12 4
Pitch = Rise/Span
expressed as fraction
reduce to smallest fraction
not placed on drawing, helpful to carpenter

13. Roof Terms
Span
Distance across the building

14. Roof Terms
Run
1/2 the distance across the building (1/2 span distance)

15. Roof Terms
Rise
The distance the roof rises (distance from the square of house to ridge)

16. Roof Terms
Pitch
The fraction of the rise over span

17. Roof Terms
Slope
Slope is stated as a ratio of rise over run with run always as 12

18. Slope vs Pitch vs Angle Slope Pitch Angle 3:12 1/8 14°0’0”
3: /8 14°0’0”
4: /6 18°30’
5: /24 22°30’
6: /4 26°30’

19. Roof Member Terminology

20. Metal Framing Connectors
Keeps structural members from separating