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LEGAL · SOURCES

Sources Policy.

Last updated: January 2026

Purpose

This document discloses the sources behind reference material shown on ConstrCalc® — guides, standard quantities, country practices, glossary. It does not disclose sources for user-supplied data, because user-supplied data has no source but the user.

Standard Material Quantities (per 1,000 ft²)

  • Cement 400 bags, sand 81.6 ton, steel 4,000 kg, bricks 8,000 pcs, aggregate 1,350 ft³, paint 2.5 gal
  • Origin: Conservative Indian/South Asian residential RCC (Reinforced Cement Concrete) construction norms popularized in field manuals and cross-referenced against practitioner data.
  • Applicability: Regional; verify locally. Use Manual Entry when standards diverge.

Cost Reference Ranges

  • Cement $6–$12/bag, sand $20–$45/ton, steel $0.60–$1.20/kg, bricks $0.25–$0.60/pc, aggregate $1.00–$2.20/ft³, paint $30–$60/gal
  • Origin: Aggregated retail/wholesale pricing from major North American home-improvement retailers and construction supplier catalogs, sampled quarterly.
  • Volatility: These are point-in-time reference values, not price predictions. Prices vary materially by location and market conditions. Always use your actual quotes in the calculator.

Country-Specific Practices

  • Origin: Publicly available national/municipal building code references (IRC/IBC USA, Building Regs UK, DIN Germany, SANS South Africa, NBR Brazil, BCA/NCC Australia, etc.) and government revenue portals for tax rates.
  • Applicability: Country practice notes are broad summaries. Consult a licensed local professional for project-specific requirements.

Glossary

  • Origin: Composite of standard construction industry usage across US, UK/Commonwealth, and international practice. Cross-regional variance (e.g., punchlist vs snag list) noted where relevant.

Labor & Permit Reference Values

  • Origin: US Bureau of Labor Statistics (BLS) for national wage benchmarks; state and municipal permit fee schedules for typical permit ranges; sampled from public data.

Currency & Unit Conversion Constants

  • Deterministic mathematical constants only:
    • 1 m² = 10.7639 ft²
    • 1 m³ = 35.3147 ft³
    • 1 US Ton = 907.185 kg; 1 Metric Ton = 1,000 kg
    • 1 US Gallon = 3.7854 L
  • Currency exchange rates shown in the selector are illustrative labels — ConstrCalc does not convert user-entered monetary values between currencies.

Correction Policy

If you find a factual error in any of our reference material, please contact us. Substantive corrections are published with a dated note on the affected page.

Not A Substitute For Professional Advice

All reference material is informational. For real-project decisions, consult a licensed professional in your jurisdiction. See our Disclaimer.