Cathedral Truss Calculator
A cathedral truss is built for a steep, dramatic roofline with an exposed or high interior ceiling — the profile behind churches, great rooms, and A-frame-style living spaces. This calculator sizes a cathedral truss from your span and pitch, returning rafter length, ridge height, roof area, and material cost.
Size Your Cathedral Truss
Enter your building specifications below. Results and the roof diagram update live as you type.
Live Roof Diagram
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Estimate Your Project Budget
Automatically calculated from your inputs above in the calculator.
Estimates only. Actual costs vary by region, supplier, and site conditions.
Cathedral Trusses vs. Scissor Trusses
A cathedral truss typically uses a steep, symmetrical pitch (often 8/12 to 12/12 or steeper) with the interior finish following the top-chord slope directly, either with an exposed structural ceiling or a raised, near-flat bottom chord set high enough to stay out of view.
Cathedral and scissor trusses both create open, high ceilings, but a scissor truss achieves the vault with a sloped bottom chord at a moderate roof pitch, while a cathedral truss relies mainly on a steeper overall roof pitch — the right choice depends on the desired ceiling shape and the building's wall height.
Steeper pitches increase rafter length, roof area, and material cost per foot of span, so use the calculator's cost estimate alongside the Pitch & Angle calculator to compare a cathedral profile against a lower-pitch alternative before finalizing a design.
Frequently Asked Questions
What pitch is used for a cathedral ceiling truss?
Cathedral truss designs commonly use pitches from 8/12 up to 12/12 or steeper, since a steeper slope is what creates the tall, dramatic interior ceiling line the style is known for.
Is a cathedral truss the same as a scissor truss?
No. Both create vaulted interiors, but a cathedral truss uses a steep overall roof pitch with the ceiling following the top chord, while a scissor truss uses a sloped bottom chord at a more moderate pitch.