1 / 15

# Presentation 27: - PowerPoint PPT Presentation

Presentation 27:. HIP JACK THEORY AND LAYOUT. Hip Jack Rafters. All jack rafters are OC rafters. They are cut shorter because of the presence of another member. For hip jacks, this member is a hip rafter. They are considered special common rafters. Hip Jack Rafters. Hip Rafter.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' Presentation 27:' - roden

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Presentation 27:

HIP JACK THEORY AND LAYOUT

• All jack rafters are OC rafters.

• They are cut shorter because of the presence of another member.

• For hip jacks, this member is a hip rafter.

• They are considered special common rafters.

Hip Rafter

Ridgeboard

Common Rafters

Hip Jack Rafters

`

`

This applies to jack rafters too.

Run is the horizontal under the rafter.

This is true for all rafters.

The red lines represent the run for each rafter.

This applies to jack rafters too.

The red distances here are the same length.

Therefore a square is formed under each pair of jack rafters.

Distance from the corner

Hip Jack Rafter Run

The jack rafter run is equal to the jack’s distance from the corner.

They are the same measurement.

45°

OC Jack Rafter Spacing

Common Difference

Hip run is at a 45° angle with the building line.

A square

is formed

Adjacent jack rafters have a difference in run that is equal to the OC spacing.

All red distances are equal

45°

Common Difference

Hip run is at a 45° angle with the building line.

Adjacent jack rafters have a difference in run that is equal to the OC spacing.

Common difference LENGTH of jack rafters

Common difference in RUN of jack rafters

OC Jack Rafter Spacing

All red distances are equal

Common Difference

Common difference in length (CDL) may be calculated.

CDL = OC (terms of feet) x Unit length

CDL

Or may be found on the third and fourth line on a rafter square.

• Since hip jacks are shortened OC rafters, the tails are laid out the same.

• Use the common rafter pattern.

• Hip jacks are shortened and have side cuts in the same fashion as hip rafters.

• Draw plumb line.

• Rafter is shortened for the hip ½ the diagonal thickness of the hip.

Usually 1 1/16″

• Draw a square line on the top with a center mark.

• Side cuts are made by measuring ½ the jack thickness.

Usually 1 1/16″

Usually 3/4″

• Draw angled line over the top.

• Hip jacks are OC rafters with tails the same as common rafters.

• Adjacent hip jacks have a common difference in length.

• Hip run is equal to the distance the jack is located from the building corner.

• Shortening and side cuts may be handled in the same fashion as for hip rafters.