Gambrel Angle

The Gambrel Angle calculator computes the inner angle made by two intersecting pitches.  This is common in a gambrel roof.

INSTRUCTIONS: Enter the following:

• (P1) Pitch 1
• (P2) Pitch 2

Gambrel Angle (B): The calculator returns the angle in degrees.  It also returns the Supplementary Angle (c) in degrees. However, these can be automatically converted to compatible units via the pull-down menu.

The Math / Science

The formula for the Gambrel Angle of intersection of two right triangles is:

B = 2π - π/2 - (π/2 -P1) - P2

where:

• B = Interface Angle
• P1 = Angle 1
• P2 = Angle 2

Note: P1 and P2 are two pitches.  They are converted to radian angles.

Roofing Geometries Calculators

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• Gambrel Angle: Computes the bend at the intersection of two slope as in a gambrel roof.
• Interface Angle: This computes the interface angle between two sloped surfaces.
• Interface Angle from Rise over Run: This computes the interface angle based on two rises and runs.
• Trusses Needed for a Roof: This computes the number of trusses needed for a roof based on the ridge length and truss spacing
• Roof Section Area: This computes the surface area of an irregular shaped section of a roof.
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• Hip Roof Geometries: This the metrics associated with a hip roof based on the dimensions.
• Double Hip Roof Geometries: This compute the lengths of the dimensional lines where one hip roof intersects another such as in a dormer.
• Pyramid Hip Roof Geometries: This computes the lengths and dimensional lines of a pyramid roof.
• Gambrel Pitch Angles: This computes the pitch angles and rafter lengths in a gambrel roof bases on the span, total height, and height and width of the loft.
• Gambrel Rafter Lengths. This computes the upper and lower rafter lengths, attic width and total height under a gambrel roof based on the upper and lower pitch, span and loft height.
• Rafter Length: This computes the length of the rafters based on the span, pitch and overhang.
• Corrugation Factor: This computes the material length associated with a structural length using corrugated material.

Roof Types

Roofing Calculators