Scaffold Load & Tie Calculator
Calculate scaffold platform loads, leg forces, and duty ratings per OSHA scaffold standards
This calculator estimates local scaffold platform load, leg load, mudsill area, and tie-location prompts from selected duty rows, platform dimensions, workers, material load, height, length, and bearing-surface placeholders.
The output is not scaffold design, OSHA compliance proof, a manufacturer load table, competent-person inspection, scaffold tag, erection plan, fall-protection plan, or permission to load or use a scaffold. Current OSHA/state-plan rules, manufacturer instructions, component tags, employer procedures, site conditions, qualified-person design, and competent-person authority still control.
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Select a Local Duty Prompt
Choose light, medium, heavy, or special duty as a local planning row. Replace the prompt with current manufacturer rated capacity, maximum intended load, and qualified design data before relying on it.
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Enter Platform Geometry
Enter platform width, bay length, scaffold height, loaded levels, and total length. The calculator calculates area and tie-location prompts only.
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Add Worker and Material Load Prompts
Enter worker count and material weight per loaded level. The worker row is a local worker/tools prompt; actual PPE, tools, hoists, equipment, and material weights still need field confirmation.
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Review Load and Base Prompts
Compare imposed load to the selected duty prompt and review leg load, placeholder bearing pressure, and mudsill area. Manufacturer and site foundation review are still required.
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Review Tie and Safety Warnings
Use the tie count as a source pointer for manufacturer and OSHA review. Actual ties, anchors, wind, enclosures, fall protection, access, electrical hazards, training, and competent-person decisions are outside the calculator.
Built For
- Scaffold planning teams documenting a local load prompt before manufacturer and competent-person review
- Site supervisors comparing material staging assumptions before routing a scaffold through the employer tag process
- Safety staff keeping OSHA, state-plan, fall-protection, access, electrical, and training gaps visible during review
- Scaffold users estimating how material staging affects a selected duty prompt before loading decisions are made
- Estimators and planners building a preliminary conversation around mudsill and tie-location assumptions
Features & Capabilities
Duty Prompt Comparison
Compares entered worker and material load to a selected light, medium, heavy, or user-entered duty prompt while warning that manufacturer rated capacity and maximum intended load still control.
Leg Load and Mudsill Prompt
Estimates base load, load per leg, placeholder bearing area, and a local mudsill prompt while keeping foundation, base-plate, soil, settlement, slope, drainage, and qualified-review gaps visible.
Tie Location Prompt
Shows first tie, vertical interval, horizontal interval, and tie-count prompts from OSHA 1926.451(c)(1) source boundaries, including the 20 ft prompt for scaffolds 3 ft wide or less.
Source Warnings
Keeps OSHA 1926.451, 1926.452, 1926.454, Appendix A, OSHA eTool, ANSI/ASSP A10.8, manufacturer, competent-person, and qualified-person boundaries in the report and PDF.
Assumptions
- Worker/tools load uses a local 250 lb prompt per worker, not a verified job-specific worker, PPE, tool, or carried-material weight
- Duty rows are local 25/50/75 psf prompts and must be reconciled to manufacturer rated capacity and maximum intended load
- Dead load uses a 10 psf placeholder and does not model exact frames, planks, guardrails, braces, jacks, access towers, or attachments
- Leg load assumes four equal-sharing legs in one bay; real load distribution varies by geometry, bracing, eccentric loads, and component stiffness
- Tie prompts use OSHA 1926.451(c)(1) intervals as source pointers and do not design anchors or verify the structure receiving ties
- Bearing-surface rows are placeholders and do not verify soil, slab, asphalt, mudsill, slope, drainage, or settlement behavior
Limitations
- Does not replace OSHA/state-plan compliance review, manufacturer instructions, component tags, or qualified-person design
- Does not approve erection, alteration, dismantling, loading, scaffold tag status, or worker access/use
- Does not model wind, netting, tarps, enclosures, hoists, side brackets, cantilevers, suspension systems, outriggers, casters, or eccentric loads
- Does not evaluate damaged, corroded, bent, mixed-manufacturer, modified, missing, or improperly installed components
- Does not evaluate fall protection, falling-object protection, access, electrical hazards, high winds/storms, debris, training, rescue, or employer procedures
- Does not verify foundations, base plates, mudsills, soil, asphalt, slab condition, edge distance, drainage, slope, or settlement
References
- OSHA 29 CFR 1926.451 - Scaffold general requirements
- OSHA 29 CFR 1926.452 - Additional scaffold type requirements
- OSHA 29 CFR 1926.454 - Scaffold training requirements
- OSHA 29 CFR 1926 Subpart L Appendix A - Non-mandatory scaffold specifications
- OSHA eTool - Scaffolding general requirements
- ANSI/ASSP A10.8-2019 - Scaffolding Safety Requirements source pointer