Use this construction calculation for preliminary quantity, geometry, material, load, or coverage planning when dimensions and units have been measured consistently.

Original Millimeters (mm)

Required number input.

Compressed Millimeters (mm)

Required number input.

Geometric thickness-retention fraction of insulation after compression; it is not a direct R-value correction. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Retained Fraction

The resulting retained fraction returned as a number.

• Nominal R- and U-values do not by themselves capture thermal bridges, air leakage, moisture, compression, installation gaps, surface films, aging, or whole-assembly performance. Energy-code compliance requires the prescribed assembly method.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Verify dimensions on site, use current product data and local code requirements, include an explicit waste or safety allowance where appropriate, and obtain qualified structural, electrical, plumbing, or geotechnical review when required.

• Decking Waste Factor

  Find purchased decking area needed when the supplied waste percentage is a fraction of purchased area, so usable area is purchased area×(1−waste).

• Excavation Slope Ratio

  Horizontal run per unit vertical rise of an excavation slope; this geometric ratio is not a safe-slope determination.

• Insulation Thickness From Rvalue

  Homogeneous insulation thickness from target area-specific R-value and material thermal conductivity in SI units.