1. What is Pitched Rafter Calculation?

The pitched rafter calculation determines the length of roof rafters needed for pitched roofs based on the horizontal run and the pitch angle. This is essential for proper roof construction and material estimation.

2. How Does the Calculator Work?

The calculator uses the pitched rafter formula:

Where:

• \( \text{Run} \) — Horizontal distance (meters)
• \( \text{Pitch Angle} \) — Roof angle in radians
• \( \cos \) — Cosine trigonometric function

Explanation: The formula calculates the hypotenuse of a right triangle where the run is the adjacent side and the pitched rafter is the hypotenuse.

3. Importance of Rafter Calculation

Details: Accurate rafter calculation is crucial for proper roof construction, material ordering, structural integrity, and cost estimation in building projects.

4. Using the Calculator

Tips: Enter the horizontal run in meters and the pitch angle in radians. Ensure values are valid (run > 0, pitch angle between 0-1.57 radians).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between run and rafter length?
A: Run is the horizontal distance, while rafter length is the actual diagonal length along the roof pitch.

Q2: How do I convert degrees to radians?
A: Multiply degrees by π/180 (approximately 0.0174533). For example, 30° = 30 × π/180 ≈ 0.5236 radians.

Q3: What are typical pitch angles for roofs?
A: Common residential roof pitches range from about 0.35 to 0.70 radians (20° to 40°).

Q4: Does this calculation account for overhangs?
A: No, this calculates the basic rafter length. Additional length should be added for overhangs and eaves.

Q5: Should I add extra length for cutting and fitting?
A: Yes, it's recommended to add 5-10% extra length to account for cutting waste and fitting requirements.