1. What is Roof Rafter Length?

Rafter length is the measurement from the top of the roof's ridge to the outside edge of the wall plate. It's a critical measurement in roof construction that determines the size and angle of roof framing members.

2. How Does the Calculator Work?

The calculator uses the Pythagorean theorem:

Where:

• \( \text{Rise} \) — Vertical height from top of wall to roof peak (feet)
• \( \text{Run} \) — Horizontal distance from outside of wall to center of roof (feet)

Explanation: This formula calculates the hypotenuse of a right triangle, which represents the rafter length when the rise and run form the two perpendicular sides.

3. Importance of Accurate Rafter Calculation

Details: Precise rafter measurements are essential for proper roof construction, structural integrity, material estimation, and avoiding costly construction errors.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between rise and run?
A: Rise is the vertical measurement (height), while run is the horizontal measurement (half the building width for a symmetrical roof).

Q2: How do I measure rise and run for my roof?
A: Rise is measured from the top of the wall to the peak. Run is measured from the outside of the wall to the center of the building.

Q3: Does this calculator account for roof overhang?
A: No, this calculates the basic rafter length. You'll need to add overhang length separately if needed.

Q4: Can I use this for different roof pitches?
A: Yes, this formula works for any roof pitch as long as you have accurate rise and run measurements.

Q5: Should I add any extra length for cutting?
A: Yes, it's recommended to add a few inches to your calculated length to account for cutting and fitting at the ridge and wall plate.