Calculator Usage

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The Roof Framing Help Desk app/Bot calculates rafter angles. It does not calculate rafter lengths
It can calculate the rafter angles for equal-pitched roofs, unequal-pitched roofs, and polygon roofs, like Octagon roofs.
 

 The correct syntax to send to the Bot is a comma-delimited string. Like 90,8,8. This tells the Bot to calculate the hip rafter roof framing angles for a roof with an Eave angle of 90°, and the main Pitch is 8:12, and the Adjacent Pitch is 8:12

 The Bot requires at least 3 comma-separated values, but you can send up to 7. 

Eave Angle, Main Roof Pitch, Adjacent Roof Pitch, Hip Rafter Width, Jack Rafter Spacing, Treat Main Roof Pitch and Adjacent Roof Pitch as angles in degrees

Example: 90,8,8,6,24 for an equal-pitched roof
Example: 135,8,8,6,24 for an Octagon roof
Example: 90,8,10,6,24 for an unequal-pitched roof
Example: 120,8,10,6,24 an unequal-pitched roof on a 120° eave angle
Optional Example: 90,33.69007,39.80557,6,24,1 on an unequal-pitched roof on a 90° eave angle using Roof Slope angles in degrees

1. Roof Eave Angle in degrees
2. Main Roof Pitch: 1-24
3. Adjacent Roof Pitch: 1-24
4. Hip Rafter Width:  Used for the Plumb Line Shift dimension to layout the hip rafter
5. Jack Rafter On Center Spacing:  Used to calculate the jack rafter length difference between the jack rafter lengths
6. Use Roof Slope Angles instead of Roof Pitch: 1,  90,33.69007,39.80557,6,24,1
7. Use Hip Rafter Shift: 1, to use hip rafter shift-devoiement: 90,8,10,6,24,0,1

If the eave angle = 90° and the two roof pitches are not equal, then the calculator uses the Jack Rafter On Center Spacing for the Roof Overhang Run to calculate the Hip Rafter Offset from the Corner of the plates

Roof Framing Help Desk:

Eave Angle: 90.0

Main Pitch: 8.0

Adj. Pitch: 10.0

Main Roof Slope Angle: 33.69007

Adjacent Roof Slope Angle: 39.80557

Main Plan Angle 51.34019 degrees:

Adjacent Plan Angle 38.65981 degrees:

Hip Rafter Angle 27.50055 degrees:

Hip Rafter Pitch 8.83/16.97:

Main Backing Angle 20.27452 degrees:

Adjacent Backing Angle 29.99339 degrees:

Hip Rafter Width 3.50

Hip Rafter is NOT Shifted using  dévoiement 

Main Plumb Line Shift 1.40

Adjacent Plumb Line Shift 2.19

Jack Rafter Spacing 24.00

Main Jack Rafter Diff. 36.06

Adjacent Jack Rafter Diff. 24.99

Over Hang Run 24.00

Hip Rafter Offset From Corner 6.00

Offset Wall Plate Rise 4.00

Main Purlin-frieze block Miter Angle 23.93 degrees:

Main Purlin-frieze block SBBA Angle 31.32 degrees:

Adjacent Purlin-frieze block Miter Angle 38.67 degrees:

Adjacent Purlin-frieze block SBBA Angle 36.86 degrees: 

Main Roof Sheathing Angle 56.35 degrees

Adjacent Roof Sheathing Angle 46.16 degrees

Valley Sleeper SBBA 39.37

Valley Sleeper Offset dimension for a 1.5 depth sleeper: = 1.25

For Stair Calculations, simply enter the word "stairs" and the total height of the stairs separated by a comma.  Enter the total height of the stairs as a decimal number.

It will return a list of the number of risers and their heights.
Remember, there is 1 fewer tread than there are risers. If there are 16 risers, then there are 15 treads.
The possible riser height--number of riser combinations are shown for 8" to 4 1/2" riser heights
for the total height entered.
Example calculations returned from the Bot for stair calculations:

Total Height of Stairs: 121.37500
Total Height of Stairs: 121 3/8
16 Risers: with a rise of 7 9/16
17 Risers: with a rise of 7 1/8
18 Risers: with a rise of 6 3/4
19 Risers: with a rise of 6 3/8
20 Risers: with a rise of 6 1/16
21 Risers: with a rise of 5 3/4
22 Risers: with a rise of 5 1/2
23 Risers: with a rise of 5 1/4
24 Risers: with a rise of 5 1/16
25 Risers: with a rise of 4 7/8
26 Risers: with a rise of 4 11/16