SBE Builders

Strong Built Establishments Builders

SBE Builders is a commercial and residential framing contractor located in Discovery Bay California. Dedicated to the art of Carpentery & Roof Framing. We are the professionals for the future of the craft of carpentry.

Unequal Pitch Roof With Unequal Height Plate Lines Calculator
Major Rafter Pitch Or Major Pitch Angle Minor Rafter Pitch Or Minor Pitch Angle Ridge Width Building Span  
Plate Height Difference Major Rafter Seat Cut Rafter Material Depth Minor Rafter Seat Cut Minor Material Depth Overhang Show Feet Inches

Unequal Pitch Roof Trigonometry
Calculating unequal pitched roofs is easy if you know what trigonometry functions to use. The
formulas below use the law of sines to calculate the unknown length or angle.

Known Variables: Major Pitch Angle & Minor Pitch Angle & Span & Plate Line Difference
Calculate Major & Minor Runs & Theoretical Plate Line Span
Theoretical Span = Span - (Plate Line Difference  tan(Minor Pitch Angle))
Plate Line Difference Run = Span - Theoretical Span
Major Run = ((Theoretical Span  sin(Minor Pitch Angle))  sin (180 - Major Pitch Angle - Minor Pitch Angle))  cos( Major Pitch Angle )
Theoretical Minor Run = ((Theoretical Span * sin(Major Pitch Angle))  sin (180 - Major Pitch Angle - Minor Pitch Angle))  cos( Minor
Pitch Angle )
Minor Run = Theoretical Minor Run + Plate Line Difference Run
Major Rafter = Major Run  cos (Major Pitch Angle)
Theoretical Minor Rafter = Theoretical Minor Run  cos (Minor Pitch Angle)
Plate Line Difference Minor Rafter = Plate Line Difference Run  cos (Minor Pitch Angle)
Minor Rafter = Minor Run  cos (Minor Pitch Angle)
Roof Rise = Major Run  tan (Major Pitch Angle)
Total Minor Roof Rise = Minor Run  tan (Minor Pitch Angle)

Law Of Sines
C = 180 - (A + B)
a = ( c  sin( A) )  sin( C)
a = ( b  sin( A ) )  sin( B)
a = ( b  sin( B ) )  sin( A)
b = ( c  sin( B ) )  sin( C)
b = ( a  sin( B ) )  sin( A)
b = ( a  sin( A ) )  sin( B)
h = b  sin( A )
h = a  sin( B )
c = ( a  sin( C ) )  sin( A)
c = ( b  sin( C ) )  sin( B)

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SBE Builders
SBE Builders
5305 Laguna Ct.
Discovery Bay, California 94505
(925) 634-6022 • Fax: (925) 634-6022
Commercial & Residential Framing Contractor
American Carpenter and Builder
California Licensed General Building Contractor
CA LIC.#  546126

Roof Framing Geometry

  • Roof framing geometry is empirical-type knowledge.
  • Information gained by means of observation, experience, or experiment.
  • From ground Line 0: Z1, Z2, Z3 etc...
  • To Roof Axis 0: A1, A2, A3 etc...
  • To the bring back line 0 for scribing: B1, B2, B3 etc...

Roof Framing Geometry Blog

Rafter Tools for Android
With Quad Tetrahedra Analytic Algorithm Technology.
Helping apprentice carpenters on their journey to becoming master carpenters with Certification in roof framing.

Rafter Tools+ for iPhone

Rafter Tools+ is a rafter calculator for complex roof framing angles that other roof framing calculators don't offer.


Stair Tangent for iPhone

This iPhone app is for rough frame carpenters that don't build stairs everyday, but could use an stair app calculator to check their stair building calculations. Build a set of stairs that you are gonna be proud of. With Stair Tangent you can elimenate cumulative math errors when building - constructing stairs.

Stair Tangent

Crown Molding Tools

Crown Molding Tools  

Carpenters Of Steel

Canadian & American Geometric Roof Framing Development
using a Steel Framing Square

Geometric Roof Framing Development for Irregular Hip Roof Calculations
using a Steel Framing Square

Geometric Development of Tetrahedron
using a Steel Framing Square

Hip Rafter Backing Bevel Angles from 1565 to 2013

Applied Geometry and Euclidean GeometryA lesson in Applied Geometry and Euclidean Geometry

This Is Carpentry

We're a member of the Timber Framers Guild

Timber Framers Guild

American College of the Building Arts, carpentry and timber framing programs.

American College of the Building Arts

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