The frame geometry, labor productivity, and rate constants behind the scaffold calculator, each with its citation and confidence.
This is the exact table the Scaffolding Cost Calculator runs on. Cite it as: Antero Trail, "Frame scaffold constants and rates", anterotrail.com/tools/reference/scaffold-constants. Primary sources are listed with each value and at the bottom of the page.
Frame/system-scaffold coverage math + erect/dismantle productivity constants for a construction estimating tool. CITED = traceable to OSHA 29 CFR 1926 Subpart L (osha.gov) or a named supplier catalog (ScaffoldMart, Lynn Ladder). ESTIMATING-HEURISTIC = production-rate database (Methvin), a derived value, or an attributed industry rule of thumb; treat these as planning defaults, not authoritative rates. IMPORTANT: for FRAME scaffolds the 125 ft registered-PE design threshold is OSHA 1926.452(c)(6) (fabricated frame scaffolds) - 1926.451(a)(6) only requires a 'qualified person.' Productivity figures (erect_labor_hours_per_csf/per_bay) are BARE-erection outputs and read low vs a full all-in estimate; use RSMeans 01 54 23 (paywalled, not accessed) for all-in labour. No OSHA numbers were invented - all regulatory values are quoted verbatim. Values with no citable figure are null with a _note (debris netting). All access dates 2026-07-11.
| key | value | unit | confidence | note | Source |
|---|---|---|---|---|---|
| frame_width_ft | 5 | ft | cited | not published | |
| frame_height_ft | 6.33 | ft | cited | 6 ft 4 in nominal frame height (6.333 ft); the common general-construction walk-through frame size. A 7 ft frame height is also sold; this constant reflects the 6'4" walk-thru catalog item. | |
| bay_length_ft | 7 | ft | cited | Bay length = the 7 ft cross-brace run between two frame legs. | |
| sf_facade_per_bay_per_lift | 44.33 | ft2 | cited | Facade coverage per bay per lift = 7 ft wide x 6'4" (6.333 ft) tall. Both source dimensions are cited to ScaffoldMart; the product (multiplication) is arithmetic, not an independent measurement. | |
| frame_uniform_load_rating_psf | 50 | lb/ft2 | cited | not published | |
| scaffold_capacity_safety_factor | 4 | ratio | cited | not published | |
| engineering_required_height_ft | 125 | ft | cited | For FRAME scaffolds the controlling paragraph is 1926.452(c)(6), not 1926.451(a)(6). 1926.451(a)(6) only requires design by a 'qualified person.' The identical 125 ft PE rule for tube-and-coupler scaffolds is at 1926.452(b)(10). | |
| guardrail_toprail_min_height_in | 38 | in | cited | not published | |
| guardrail_toprail_max_height_in | 45 | in | cited | not published | |
| guardrail_on_open_side_height_threshold_ft | 10 | ft | cited | Above 10 ft, a guardrail system (or personal fall arrest) is required on open sides/ends. Guardrail system = toprail plus midrail per 1926.451(g)(4)(iv). | |
| platform_fully_planked_required | yes | boolean | cited | not published | |
| planks_per_bay | 7 | count | estimating-heuristic | Assumes nominal 2x10 wood planks across a 5 ft walk-thru frame. Aluminum/plywood deck systems (e.g. 19"-wide alum-ply platforms) need ~3-4 units per bay instead. Verify against the actual deck product on the job. | |
| erect_production_rate_m_run_per_labor_hour | 3.9 | m_run_per_labor_hour | estimating-heuristic | Bare-erection output rate for tube-and-fitting scaffold, single erector. Range 3.2-4.6 m/hr; value is the midpoint. | |
| erect_labor_hours_per_bay | 0.55 | labor_hours_per_bay_per_lift | estimating-heuristic | Bare frame/tube erection only. Excludes mobilization, base/mudsill setup, planking, guardrails, ties/bracing, and access. Real all-in labour per bay is typically several times this; confirm against RSMeans 01 54 23 or a local scaffold sub. | |
| erect_labor_hours_per_csf | 1.2 | labor_hours_per_100_ft2_facade | estimating-heuristic | This is a BARE-erection output figure and reads low for a full estimate. All-in frame-scaffold erection (mob, base, planking, guardrails, bracing, ties, access, safety) commonly runs materially higher per CSF. Use RSMeans Building Construction Cost Data section 01 54 23 (Temporary Scaffolding & Platforms) for an all-in figure; that data is paywalled and was not accessed here. | |
| dismantle_factor | 0.5 | ratio_of_erect_time | estimating-heuristic | The ~0.5x rule of thumb is widely used. NOTE the Methvin table's 'striking' line was read as '200% x erect' (i.e. it may express dismantle differently or the reading is ambiguous); do not treat 0.5 as authoritative. Confirm the dismantle basis with the scaffold sub. Value kept at the conventional 0.5. | |
| debris_netting_cost_per_sf_usd | not published | usd_per_ft2 | estimating-heuristic | No verified free public $/SF figure for installed scaffold debris netting was found. Material-only rolls are inexpensive but installed cost varies by grade (fire-retardant vs standard), wind exposure, and region. Quote locally. (Reference context only, not a usable rate: one 2025 guide cited whole-scaffold enclosure at ~$18-40/SF in NYC, https://nycbestscaffold.com/scaffolding-nyc-costs-2025-save-money-without-risking-safety/ accessed 2026-07-11 - that is total scaffold, not netting alone.) |
These calculators produce planning estimates from published public rate schedules. They are not a formal quote. Confirm equipment, access, and pricing with a licensed operator or rental yard before you rely on any number for an estimate.