Rafter Spacing Calculator
Calculate rafter spacing for roof construction based on building codes, rafter size, roof span, and load requirements. Get accurate rafter layout for your roofing project.
Step 1: Roof Dimensions
Understanding Rafter Spacing
Standard rafter spacing is typically 16″ or 24″ on center. Closer spacing (12″) provides more support for heavy loads, while wider spacing (24″) reduces materials but requires larger rafters.
Step 2: Load & Options
Building Code Compliance
Most building codes require rafter spacing of 16″ or 24″ on center for residential construction. Always check local building codes for specific requirements in your area.
Rafter Spacing Results
Recommended Rafter Spacing
Rafter Spacing Comparison
| Spacing (OC) | Number of Rafters | Total Length | Load Capacity | Material Cost |
|---|
Rafter Layout Analysis
Rafter Spacing Formula
Number of Rafters = (Span × 12) / Spacing + 1
The number of rafters is calculated by converting the span to inches, dividing by the spacing, and adding one for the end rafter. Actual spacing may be adjusted slightly to ensure even distribution across the span.
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