Gambrel Roof Geometry Calculator
Calculators - Estimators - Template Generators
Tell a Friend!
This Gambrel Roof confines to a semicircle, and starts as the top half of an equal sided octagon.
Move slider or directly enter angle to alter sweep angle of lower rafters and change the shape.
to calculate rafter overhang equal to the lower level cut at the full rafter depth.
With overhang selected, move the slider to increment - decrement the birdsmouth seat width to suit.
Geometric calculator only. Check local building regulations for sizes, spans angles etc.
If using gussets to connect rafters, check the Gussets
box and enter Gusset Base width to create gusset dimension diagrams. (see diagrams)
Left click, release and drag in main diagram to directly measure dimensions at scale
Email this Calculation
Need these calculations on-site? Try the site with an iPad or Android Tablet. With a tablet, you can directly measure angles for input to the Roofing and Pitch Angle calculator apps.
Lay the tablet on an incline and tap to measure angle. Tap again to capture angle and auto calculate roof, pitch, angles etc.
The buttons appear automatically when you visit with a device capable of pitch measurement.
View page on Phone
Create PDF files to print diagrams on current page.
Printing to Scale Help
and Plan Printing.
To fine tune Slider Controls click to select and use ◄ ►
(cursor) keyboard keys.
Your iPhone or Android is a valuable On-Site tool!
Lay your device on an angled surface (roof ?) to directly measure angles and automatically calculate Roofing
and Pitch Angle Apps
Please help spread the word about this free service - Tell a Friend
Questions or Suggestions? ph: +61 7 40987645
ALWAYS CHECK WITH YOUR LOCAL BUILDING AUTHORITY BEFORE LAYING OUT OR BUILDING ANYTHING
AND FOLLOW ALL LOCAL CODES. VERIFY ALL DIMENSIONS AND ANGLES BEFORE CONSTRUCTION.
All calculators on this site are GEOMETRIC only. Check local regulations for sizes, spacings and all engineering requirements.
Copyright © Greg Tarrant - blocklayer.com