Roof Framing Help Desk

Roof Framing Help Desk

About this app

The Roof Framing Help Desk app/Bot is designed to serve as a knowledge base for roof framing techniques and to calculate rafter angles and rafter lengths. It can calculate the rafter angles for equal-pitched, unequal-pitched, and polygon roofs, such as Octagon roofs. It is also a knowledge base for roof framing. Enter a keyword like 'irregular hip roof,' and it will provide you with a link to a web page with explanations on cutting an irregular hip roof. Or enter a keyword like devioement-hip shift, and it will provide you with a link to a webpage for devoiement. Or how to lay out a hip rafter precisely. It will calculate rafter angles and rafter lengths.

There are currently over 300 keywords to search the knowledge database. Over 800 drawings explaining different roof framing techniques, as well as 150 new webpages of information for the keywords in the knowledge database. If you have a webpage, PDF file, or YouTube video you would like to share, you can add it to the knowledge database. The main concept of the knowledge database is to make it similar to Wikipedia, except for roof framing techniques.

Menu selection
Live Knowledge Database-> Search the Live database on our server
Static Knowledge Database-> Database is locally stored and not updated
Irregular Hip Roof Calculator-> Returns all the calculations to cut an irregular hip roof
Number of Risers-> Simple stair rise height-riser count calculator
Submit New Keywords -> Submit new keywords to be added to the Database
Books on Geometry -> Books on Geometry, Stereotomy, Trigonometry, Roof Framing
Posters & Study Resources -> PDF file links
Settings -> Control screen animations


Use the built-in rafter length calculator for irregular hip roofs. Include the hip rafter offset calculations for equal overhang.

Example results for the Irregular Hip Roof Rafter Calculator:

Roof Eave Angle: 90
Main Pitch: 8.0
Adjacent Pitch: 11.0
Main Slope: 33.69007
Adjacent Slope: 42.51045
Main Plan Angle: 53.97263
Adjacent Plan Angle: 36.02737
Hip Rafter Slope: 28.33166
Main Backing Angle: 19.04187
Adjacent Backing Angle: 33.12606

Hip Rafter Width 3.5
Hip Rafter is not Shifted
Main Backing Depth 19/32"
Adjacent Backing Depth 1 1/8"
Main Plumb Line Shift 1 9/32"
Adjacent Plumb Line Shift 2 13/32"

Hip Rafter Length: 168 9/16"
Hip Rafter Length To Ridge: 167 17/32"
Hip Rafter SBBA at Ridge: 36.02737
Main Rafter Run: 120"
Main Rafter Length: 144 7/32"
Main Rafter Length To Ridge: 143 5/16"
Adjacent Rafter Run: 87 9/32"
Adjacent Rafter Length: 118 3/8"
Adjacent Rafter Length To Ridge: 117 3/8"
Rise: 80"
Rise To Ridge: 79 1/2"
Top of Ridge: 79 1/2" + HAP

Main Purlin Miter Angle: 21.97005
Main Purlin Bevel Angle: 29.30039
Adjacent Purlin Miter Angle: 42.89582
Adjacent Purlin Bevel Angle: 36.59559

Main Roof Sheathing Angle: 58.82
Adjacent Roof Sheathing Angle: 44.61

Jack Rafter Spacing: 16.0
Main Jack Rafter Length Difference: 26 7/16"
Main Jack Rafter SBBA: 53.97263
Main First Jack Rafter Length: 24 3/32"
Adjacent Jack Rafter Length Difference: 15 25/32"
Adjacent Jack Rafter SBBA: 36.02737
Adjacent First Jack Rafter Length: 13 19/32"

Valley Sleeper SBBA: 37.83207
Valley Sleeper Offset: 1 5/32"

For Equal Overhang Roofs
Using Hip Rafter Offset
Over Hang Run 12.0
Hip Rafter Offset From Corner 4 1/2"
Offset Wall Plate Rise 3"
Main Rafter Run 120"
Adjacent Rafter Run 84"
Offset Wall Plate Length 115 1/2"
Adjacent Rafter Length 113 15/16"
Adjacent Hip Rafter Run 142 13/16"
Adjacent Hip Rafter Length 162 1/4"
Adjacent Hip Rafter Length To Ridge 161 13/32"
Main Jack Rafter at Corner Theoretical 5 13/32"
Main Jack Rafter at Corner Long Point 4 5/16"
Main First Jack Rafter Long Point 29 1/2"
Adjacent First Jack Rafter Long Point 13 19/32"
Main Overhang Rafter Length 14 13/32"
Adjacent Overhang Rafter Length 16 9/32"
Hip Rafter Overhang Rafter Length 23 3/16"

Here's a link to the help files
https://www.raftertools.com/bot/index.html