1. What is Roof Truss Length?

The roof truss length is the measurement along the slope of the roof from the outside edge of the wall plate to the center of the ridge. It's a crucial measurement for roof construction and material estimation.

2. How Does the Calculator Work?

The calculator uses the roof truss length formula:

Where:

• \( Span \) — The horizontal distance between the outside edges of the walls (ft)
• \( Pitch\,Angle \) — The angle of the roof slope (degrees)

Explanation: The formula accounts for the trigonometric relationship between the span, pitch angle, and the actual length along the roof slope.

3. Importance of Accurate Truss Calculation

Details: Accurate truss length calculation is essential for proper roof construction, material ordering, and structural integrity. Incorrect measurements can lead to construction problems and material waste.

4. Using the Calculator

Tips: Enter the span in feet and the pitch angle in degrees. The pitch angle is typically between 15° and 45° for most residential roofs.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between span and run?
A: Span is the total horizontal distance between the outside edges of the walls, while run is half the span (distance from wall to ridge).

Q2: How does pitch angle affect truss length?
A: Steeper pitch angles result in longer truss lengths for the same span, while shallower angles produce shorter truss lengths.

Q3: What are common roof pitch angles?
A: Common residential pitches range from 4/12 (18.43°) to 12/12 (45°), with 6/12 (26.57°) being very common.

Q4: Can I use this for irregular roof shapes?
A: This calculator is for simple gable roofs. Complex roof designs may require more specialized calculations.

Q5: Should I add overhang to this calculation?
A: This calculates the basic truss length. You'll need to add any desired overhang separately to get the total rafter length.