Mineral Wool thickness needed to match ThermaCote® performance at 1mm

In this article we show how ThermaCote® compares to Mineral Wool insulation. You might be surprised just how much thinner ThermaCote® application is compared to the equivalent in Mineral Wool!

Published: Mar 8, 2025

Author: ThermaCote® UK

Thermal Conductivity of Rockwool Products

  1. ThermalRock S Series:
    • S40 (Density: 40 kg/m³): λ = 0.037 W/m·K​
    • S50 (Density: 50 kg/m³): λ = 0.036 W/m·K​
    • S60 to S100 (Densities: 60-100 kg/m³): λ = 0.036 W/m·K​
  2. Thermal Insulation Roll:
    • Density: Not specified​
    • Thermal Conductivity: λ = 0.044 W/m·K (source ​rockwool.com)

ThermaCote’s R-Value at 1mm

ThermaCote achieves an R-value of 1.87 m²·K/W at a 1mm thickness.

Calculating Required Thickness to Match ThermaCote’s R-Value:

To determine the necessary thickness of Rockwool to match this R-value, we use the formula:​

Thickness = R x λ

Applying this:

For ThermalRock S50 (λ = 0.036 W/m·K):

  • Thickness = 1.87m².K/W x 0.036W/m.K
  • = 0.06732m or 67.32mm

For Thermal Insulation Roll (λ = 0.044 W/m·K):

  • Thickness = 1.87m².K/W x 0.044W/m.K
  • = 0.08228m or 82.28mm

Comparison

As you can see, in comparison, ThermaCote offers excellent performance.

  • ThermaCote’s R-value 1.87 m²·K/W at 1mm
  • ThermalRock S50 equivalent R-value approximately 67.32 mm​
  • Thermal Insulation Roll equivalent R-value approximately 82.28 mm​
A picture of mineral wool insulation
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