1. HIP RAFTER THEORY AND SAMPLE CALCULATIONS
Presentation 21:
HIP RAFTER THEORY AND SAMPLE CALCULATIONS

2. Hip Roof System
Ridge
Hip Rafters
Common Rafters
Jack Rafters

3. Hip Unit Run Hip Unit Run is 16.97″
It is found from the diagonal of a 12″ square.
16.97″
12″
This square sits on the top corner of the top plates.
12″

4. Hip Unit Run
16.97″
12″
12″

5. Hip Unit Run For every common Unit of Run …
Unit Rise
For every common Unit of Run …
Common Rafter
Common Rafter
there is a hip Unit of Run.
12″
Hip Rafter
16.97″
12″
Each has a Unit of Rise with it.
Hip and common rafters slope at different rates.

6. Ridge Shortening
Hip must also be shortened because of the thickness of the ridge.

7. Ridge Shortening Zooming in and viewing from above.
Because the common rafters and ridge are already in place when the hip is installed, the hip must be shortened.
Hip
Common
Common
Ridge
This distance is one-half of the diagonal thickness of the ridge.
Common
Hip
Usually 1 1/16″

8. Ridge Shortening
This amount is the same for hips with no common rafters nearby.
Ridge
Hip
Amount is also 1 1/16″
1 1/16″

9. Side Cuts The angle cuts are called side or cheek cuts. Hip Ridge
Common
Hip
Ridge

10. Conclusions A hip roof has more members than a gable roof.
Jack rafters are OC commons that are cut shorter to meet the hip.
Hip Unit Run is 16.97″, the diagonal of a 12″ square.
Shortening at the ridge is 1 1/16″