Roof Truss Calculator

What is a Roof Truss Calculator?

A Roof Truss Calculator estimates the number of roof trusses needed for a roof based on its span, length, and truss spacing, along with an approximate lumber requirement for construction.

Roof trusses are pre-engineered structural components that support the roof. This calculator assumes standard truss designs (e.g., gable trusses) and includes a waste factor for lumber estimates.

Gable Truss vs. Hip Truss vs. Scissor Truss

Truss Type	Use Case	Complexity	Cost
Gable Truss	Standard pitched roofs	Simple	Low
Hip Truss	Hip roof designs	Moderate	Moderate
Scissor Truss	Vaulted ceilings	Complex	High

How to Use the Roof Truss Calculator

Roof Span: Enter the horizontal span of the roof (distance between exterior walls).
Roof Length: Input the length of the roof along the ridge.
Truss Spacing: Select the spacing between trusses (e.g., 24 inches on center).
Unit: Choose the unit of measurement (feet or meters).
Calculate: Determine the number of trusses and estimated lumber requirements.

Lumber Requirements by Truss Type (Board Feet)

Comparison based on a 24 ft span and 24-inch spacing

Additional Information for Roof Truss Planning

Truss Design Considerations: Ensure proper load-bearing capacity (e.g., snow load, wind load) and consult local building codes for truss specifications.

Cost Factors: Truss costs vary by material (wood vs. steel), span, and design complexity. On average, wood trusses cost $5-10 per linear foot of span.

Installation Tips: Use professional installers for safety and precision. Pre-fabricated trusses reduce on-site labor but require accurate measurements.

Frequently Asked Questions (FAQ)

Does the calculator account for overhangs?

No, this calculator assumes the span is the distance between exterior walls. Add overhang lengths to the span for more accurate results.

Can I use this for complex roof designs?

This calculator is designed for simple gable roofs. For complex designs like hip or mansard roofs, consult a structural engineer or measure each section separately.

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Calculation Results