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IRC 2021 Residential Load-Bearing Wall Calculator
How to Use This Calculator
This tool estimates required stud size for load-bearing walls based on IRC 2021 and NDS 2018 (referenced for wood design). Follow these steps:
- Wall Height: Enter height in feet (max 12ft per IRC; >12ft requires engineering).
- Supported Load: Enter total axial load from above in plf (pounds per linear foot).
- Stud Spacing: Select spacing in inches on center.
- Wood Species: Choose species and grade (No. 2).
- Wall Type: Select interior (axial only) or exterior (conservative wind adjustment).
- Click “Calculate” to see results.
Note: Assumes single-story, typical conditions, axial loads only for interior; exterior reduces capacity ~20% for bending (simplified; actual wind calc needed). Capacities calculated dynamically per NDS.
Blocking Recommendation: For walls >8ft, add mid-height blocking for stability per IRC.
Reference Stud Capacity Table at 10ft Height (plf)
| Stud Size | 12″ Spacing | 16″ Spacing | 24″ Spacing |
|---|
Capacities calculated per NDS 2018 (axial only; adjust for actual height in results).
Results
| Required Stud Size | |
|---|---|
| Maximum Allowable Load per Stud (lbs) | |
| Load per Stud (lbs) | |
| Maximum Allowable Wall Load (plf) | |
| Status |
Results based on NDS 2018 axial capacity (Cp adjusted for height). For exterior walls, a conservative 20% reduction applied for bending; verify wind loads separately.
Disclaimer: This tool provides estimates based on IRC 2021 and NDS 2018. It assumes axial loads; lateral/wind/seismic must be checked separately. For design, consult a licensed structural engineer. Verify with official IRC tables (e.g., R602.3(5) for prescriptive limits).
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