Pro
Now with brand presets, code-edition R-target shortcuts, and supplier pack sizes. Presets are illustrative defaults—verify against current manufacturer data and your local energy code.
Formulas Used
- Area (each zone): gross = width × height; net = gross − openings.
- Total net area: sum of all zone net areas.
- Coverage per sheet: boardWidth × boardLength.
- Allowance: allowance% = waste% + stagger%.
- Sheets before waste: totalNetArea ÷ coveragePerSheet.
- Sheets per layer (rounded): ceil( sheetsBeforeWaste × (1 + allowance%/100) ).
- Total sheets: sheetsPerLayer × layers.
- Bundles: ceil( totalSheets ÷ sheetsPerBundle ).
- Effective R-value: R = (R_per_inch(material or brand) × thickness_in_inches) × layers.
- U-factor: U = 1 ÷ R (ignores thermal bridging and fasteners).
- Fasteners: totalSheets × fastenersPerSheet.
- Adhesive tubes: ceil( totalNetArea ÷ coveragePerTube ).
- Costs: boardsCost = totalSheets × sheetCost; fastenersCost = fastenersQty × costPerFastener; adhesiveCost = adhesiveQty × costPerTube; totalCost = sum.
Real installations may require edge taping, air-barrier, or weather-barrier layers. Adjust allowances accordingly.
How to Use This Calculator
- Select Units and Material type, then set layer count and thickness.
- Pick a Brand/Product or Board size preset and adjust dimensions.
- Add Areas to Cover rows for walls or surfaces, subtracting openings.
- Set Waste and optional Staggered seam allowance to capture cut losses.
- Optionally configure Fasteners, Adhesive coverage, Packs, and Costs.
- Use Code presets to quickly set CI or assembly targets. Export CSV or PDF.
FAQs
Polyiso offers higher R per inch but may vary in colder conditions. XPS provides stable R and moisture resistance. EPS is cost-effective with lower R per inch. Check local code and climate.
We use typical published R per inch values or brand overrides. Actual performance depends on brand, facing, temperature, and installation quality. Always consult manufacturer data sheets and code compliance requirements.
No. This tool assumes continuous insulation coverage. Thermal bridging through studs or fasteners is not modeled. For assemblies, use energy-modeling tools or code-specific tables to adjust.
Straight layouts can be as low as 5–7%. Complex geometry, window density, or multi-layer staggering may require 10–15% or more. Field conditions and crew experience strongly influence required allowance.
Yes, but this calculator applies a single thickness and material to all layers for simplicity. For mixed stacks, calculate layer-by-layer R and sum, or enter an equivalent thickness.
Fasteners scale with total sheets and a chosen pattern. Adhesives estimate uses net area divided by coverage per tube. Always follow manufacturer spacing, bead patterns, and curing guidelines.
Disclaimer: Presets are examples to speed planning. Verify with current manufacturer literature, local codes, and stamped drawings where required.