1. What is Rafter Length?

Rafter length is the diagonal measurement from the outside of the wall plate to the center of the ridge board in roof framing. It's a crucial measurement in roof construction and carpentry.

2. How Does the Calculator Work?

The calculator uses the Pythagorean theorem:

Where:

• \( \text{Run} \) — Horizontal distance from wall to ridge (feet)
• \( \text{Rise} \) — Vertical height from wall to ridge (feet)

Explanation: The formula calculates the hypotenuse (rafter length) of a right triangle where the run and rise are the other two sides.

3. Importance of Rafter Calculation

Details: Accurate rafter length calculation is essential for proper roof construction, material estimation, and ensuring structural integrity.

4. Using the Calculator

Tips: Enter run and rise in feet. Both values must be positive numbers. The calculator will compute the diagonal rafter length.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between run and span?
A: Run is half the span (total width of the building). For a 20-foot span, the run would be 10 feet.

Q2: How do I measure rise?
A: Rise is the vertical distance from the top of the wall plate to the ridge. It's often determined by the roof pitch.

Q3: Does this work for any roof pitch?
A: Yes, as long as you know the run and rise, this formula works for any pitch.

Q4: Should I add any extra length?
A: You may need to add overhang length to the calculated rafter length for practical construction purposes.

Q5: Can I use this for metric measurements?
A: Yes, as long as both run and rise are in the same units (e.g., both in meters).