Figure

Roof and stairs

Hip, valley and jack rafters

Read the regular-roof rafter results using pitch, run, and on-center spacing.1

A regular roof uses equal pitches on its adjoining sides. Pitch, run and on-center spacing establish the hip or valley and its jack-rafter sequence. The saved jack-order setting controls how the length list is presented.

Regular hip and jacks

For a regular roof, run is half the span. Use your pitch and on-center spacing.

Settings for this example

Jack-rafter order
Longest first

Start a new calculation

Use 2nd if a unit is above its button.

  1. Start fresh

    Press Clear entry, then Clear entry.

  2. Press the keys

    Press Select length units.

Open Roof

Skip if Roof is already open. Skip Close if no mode is open.

  1. Press Close calculation mode, then Open Roof.

1. Set the spacing

  1. Spacing in inches

    Press 16, then inches, then Store spacing.

  2. Clear the entry

    Press Clear entry.

2. Enter Run

  1. Run

    Press 6, then feet, then Store run.

3. Enter Pitch 1

  1. Pitch per foot

    Press 9, then inches, then Store pitch 1.

4. Start the jack list

Shortest first starts at 0. Keep pressing = to reach the lengths.

  1. Press the keys

    Press Select Jacks group.

  2. Complete the value

    Press Equals.

Results in orderPress = to continue

  1. Example · first jack (Longest first)5 feet 10 inches
  2. Remaining jack lengths and 0
  3. Plumb cut
  4. Level cut
  5. Cheek cut
  6. Spacing again

Longest first: lengths, then 0. Shortest first: 0, then lengths. The cuts follow the length list. Keep pressing =.

If the order differs

Jack-rafter order controls the list. Shortest first starts at 0; continue for the lengths. Spacing and pitch stay saved. Lengths exclude overhang and ridge adjustments.

Common rafter (optional)

  1. Press Select Common group.
  1. Example · Common-rafter length7 feet 6 inches

Hip or valley (optional)

  1. Press Select Hip/Valley group.

Results in orderPress = to continue

  1. Example · Hip or valley length9 feet 7 and 1/4 inches
  2. Plumb cutabout 27.94°
  3. Level cutabout 62.06°
  4. Cheek cut45°
  5. Back to hip / valley9 feet 7 and 1/4 inches

Display assumptions

  1. Fraction precision: 1/16″; Fraction format: Simplified; Angle decimal places: Variable. ↩

Keep the guide beside your calculation.

These examples are built into Figure. Open Help while you calculate, then return to the same guide and reading position.

See Help in Figure →