Figure

Roof and stairs

Irregular roofs

Calculate hip, valley, and jack results for two roof pitches and compare jack spacing and ordering.1

Different roof pitches produce different lengths, cuts and jack spacing on the two sides. Keep Pitch 1 and Pitch 2 attached to the correct sides of the sketch, and review the saved alignment and ordering settings with each example.

Irregular hip/valley cuts

Use Run for the Pitch 1 side. Enter Pitch 1, Pitch 2 and spacing.

Settings for this example

Jack-rafter order
Longest first
Pitch 2 jack spacing
Equal on-center spacing

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.

Enter and calculate

  1. Pitch 1 per foot

    Press 7, then inches, then Store pitch 1.

  2. Pitch 1 run

    Press 4, then feet, then Store run.

  3. Spacing in inches

    Press 16, then inches, then Store spacing.

  4. Pitch 2 per foot

    Press 8, then inches, then Store pitch 2.

  5. Press the keys

    Press Select Hip/Valley group.

Results in orderPress = to continue

  1. Example result5 feet 9 and 11/16 inches
  2. Pitch 2 jack lengths
  3. Pitch 2 cuts
  4. Pitch 1 spacing
  5. Pitch 1 jack lengths
  6. Pitch 1 cuts
  7. Pitch 2 spacing again

Keep pressing = for both sides. Longest first ends each length list at 0; Shortest first starts it at 0. Cuts follow each list. Spacing and alignment affect the lengths.

Keep in mind

The second pitch is temporary: C → C removes it. Pitch 1 and on-center spacing remain saved. Cut labels follow the selected Pitch 1/Pitch 2 sides.

Read both jack sides

Use Run for the Pitch 1 side. Enter Pitch 1, Pitch 2 and spacing.

Settings for this example

Jack-rafter order
Longest first
Pitch 2 jack spacing
Equal on-center spacing

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.

Enter and calculate

  1. Pitch 1 per foot

    Press 7, then inches, then Store pitch 1.

  2. Pitch 1 run

    Press 4, then feet, then Store run.

  3. Spacing in inches

    Press 16, then inches, then Store spacing.

  4. Pitch 2 per foot

    Press 8, then inches, then Store pitch 2.

  5. Press the keys

    Press Second, then Select Pitch 2 jacks.

Results in orderPress = to continue

  1. Example result16 inches
  2. Pitch 2 jack lengths
  3. Pitch 2 cuts
  4. Pitch 1 spacing
  5. Pitch 1 jack lengths
  6. Pitch 1 cuts
  7. Pitch 2 spacing again

Keep pressing = for both sides. Longest first ends each length list at 0; Shortest first starts it at 0. Cuts follow each list. Spacing and alignment affect the lengths.

Keep in mind

Jack-rafter order and Pitch 2 jack spacing control the list. Shortest first starts each side at 0. Keep pressing = for its lengths and cuts, then the other side.

Show shortest jacks first

Choose Jack-rafter order: Shortest first, then enter the roof inputs.

Settings for this example

Pitch 2 jack spacing
Equal on-center spacing

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.

Set the calculation option

Jack-rafter order
Shortest first

Open Roof

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

  1. Press Close calculation mode, then Open Roof.

Enter and calculate

  1. Pitch 1 per foot

    Press 7, then inches, then Store pitch 1.

  2. Pitch 1 run

    Press 4, then feet, then Store run.

  3. Spacing in inches

    Press 16, then inches, then Store spacing.

  4. Pitch 2 per foot

    Press 8, then inches, then Store pitch 2.

  5. Press the keys

    Press Second, then Select Pitch 2 jacks.

Results in orderPress = to continue

  1. Example result16 inches
  2. Pitch 2 jack lengths
  3. Pitch 2 cuts
  4. Pitch 1 spacing
  5. Pitch 1 jack lengths
  6. Pitch 1 cuts
  7. Pitch 2 spacing again

Keep pressing = for both sides. Longest first ends each length list at 0; Shortest first starts it at 0. Cuts follow each list. Spacing and alignment affect the lengths.

Keep in mind

The manual offers ascending order but does not fully specify terminal-zero numbering. This example describes the app's tested list; handheld numbering has not been confirmed.

Align opposing jack rafters

Choose Pitch 2 jack spacing: Align opposing rafters, then enter the roof inputs.

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.

Set the calculation option

Pitch 2 jack spacing
Align opposing rafters

Open Roof

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

  1. Press Close calculation mode, then Open Roof.

Enter and calculate

  1. Pitch 1 per foot

    Press 7, then inches, then Store pitch 1.

  2. Pitch 1 run

    Press 4, then feet, then Store run.

  3. Spacing in inches

    Press 16, then inches, then Store spacing.

  4. Pitch 2 per foot

    Press 8, then inches, then Store pitch 2.

  5. Press the keys

    Press Second, then Select Pitch 2 jacks.

Results in orderPress = to continue

  1. Example result18 and 5/16 inches
  2. Pitch 2 jack lengths
  3. Pitch 2 cuts
  4. Pitch 1 spacing
  5. Pitch 1 jack lengths
  6. Pitch 1 cuts
  7. Pitch 2 spacing again

Keep pressing = for both sides. Longest first ends each length list at 0; Shortest first starts it at 0. Cuts follow each list. Spacing and alignment affect the lengths.

Keep in mind

Mate spacing differs on the two sides. The guide names this option without defining its reference side; this common-side anchor is the app's tested behavior, not a confirmed handheld detail.

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 →