Formula Sources
CrewMeasure formulas should be transparent enough for a contractor, estimator, reviewer, or future partner to understand what a result means and where its limits are.
Source Policy
Each calculator should identify:
- Formula or table used.
- Source name and edition where applicable.
- Supported input range.
- Assumptions.
- Rounding rule.
- Waste-factor rule.
- Output units.
- Last reviewed date.
- Whether the result is a material estimate, layout reference, structural reference, electrical reference, plumbing reference, or code-sensitive warning.
Reference Sources We Use
| Area | Source basis | How CrewMeasure uses it |
|---|---|---|
| Deck framing and joist spans | American Wood Council deck-span guidance, including DCA 6-style residential deck references where supported | Used as reference-table data for supported species, sizes, spacing, and load assumptions. Unsupported combinations should warn rather than guess. |
| Roof and rafter references | International Residential Code and International Building Code rafter-span tables, with AWC/NDS design values as the engineering basis where applicable | Used for common rafter-span references and roof framing assumptions where the calculator has supported table data. |
| Electrical planning | National Electrical Code references, including conductor, conduit-fill, box-fill, circuit, and voltage-drop planning concepts where supported | Used as field-reference math and table-based checks. CrewMeasure does not replace a licensed electrician or local electrical inspection. |
| Plumbing rough-in references | International Plumbing Code drainage fixture unit and drain-capacity concepts where supported | Used for supported fixture-unit and drain-sizing references. Local amendments, venting, slope, cleanout, and developed-length requirements still need trade review. |
| Concrete, masonry, gravel, trench, and drain quantities | Standard construction volume formulas and material-yield assumptions | Used to convert dimensions into cubic feet, cubic yards, bags, blocks, aggregate, or excavation quantities. Supplier yield and field conditions can change orders. |
| Roofing material quantities | Standard roof-area, square, bundle, sheathing-panel, soffit, fascia, gutter, and downspout quantity math | Used for material planning with visible waste and rounding assumptions. Product-specific coverage and installation instructions still control the final order. |
| Framing and panel quantities | Standard stud spacing, wall-length, opening, plate, board-foot, and panel-coverage formulas | Used to estimate material counts and cut-list starting points. Structural loads, headers, bracing, connectors, and local code still require verification. |
| Stairs, ramps, ladders, and offsets | Common geometry, rise/run relationships, slope ratios, trigonometry, and model-code reference limits where supported | Used for layout planning and warning ranges, not as a permit-ready design. |
| Finish materials | Manufacturer-style coverage math for drywall, insulation, paint, flooring, trim, tile, wallpaper, epoxy, caulk, and sealant | Used to estimate purchase quantities from area, length, coverage, waste, coats, pattern, or bead assumptions. Product labels and installation instructions remain authoritative. |
What "Code-Referenced" Means
Code-referenced means a calculator uses a model-code table, model-code concept, or trade reference as part of its calculation or warning logic. It does not mean the result is approved for your jurisdiction.
Local jurisdictions can adopt different editions, amend model codes, or require details that a generic calculator cannot see. Manufacturers can also require installation methods, fasteners, spacing, coverage, preparation, or environmental limits that change the final answer.
Important Limits
CrewMeasure may reference model-code tables or industry sources, but local jurisdictions can amend adopted codes. Manufacturers can impose product-specific installation requirements. Field conditions can invalidate a generic formula. Treat code-sensitive outputs as a starting point for review, not as an approval.
Correction Process
Formula feedback should include:
- Calculator name and URL.
- Inputs entered.
- Output shown.
- Expected output.
- Source or reasoning for the correction.
- Jurisdiction or product context, if relevant.
Send formula feedback to contact@crewmeasure.com.