Insulation·concrete 20mm
concrete · 20mm
R 0.01
U 5.479 W/m²·K

concrete, 20 mm — R 0.01

20 mm divided by a conductivity of 1.6 gives an R-value of 0.01. The U-value is 5.479, so a square metre leaks 109.59 W across a 20-degree difference.

Standards it meets

Not up to any of them yet

Material
concrete
Thickness
20 mm
Thermal conductivity
1.6 W/m·K
Thermal resistance
0.01 m²·K/W
U-value
5.479 W/m²·K
Heat lost per square metre
109.59 W
As concrete
0.02 m

Thickness for the same performance

This is the number that shows what insulation is worth. Matching 100 mm of XPS with concrete alone would take 5.7 metres of it. No one builds a wall like that — which is why a concrete building only gets warm once a thin layer of insulation is added.

  • vacuum panel0 mm
  • phenolic foam0 mm
  • rigid polyurethane0 mm
  • extruded polystyrene0 mm
  • graphite EPS0 mm
  • white EPS0 mm
  • glass wool0 mm
  • mineral wool1 mm
  • cellulose1 mm
  • timber2 mm
  • plasterboard2 mm

Nearby cells

concrete 10mm
R 0.01
concrete 30mm
R 0.02
plasterboard 20mm
R 0.11

Same material, other thicknesses

concrete 10mm
R 0.01
concrete 20mm
R 0.01
concrete 30mm
R 0.02
concrete 50mm
R 0.03
concrete 70mm
R 0.04
concrete 100mm
R 0.06
concrete 120mm
R 0.08
concrete 150mm
R 0.09
concrete 200mm
R 0.13
concrete 250mm
R 0.16
concrete 300mm
R 0.19
concrete 400mm
R 0.25

Same thickness, other materials

vacuum panel 20mm
R 2.86
phenolic foam 20mm
R 1
rigid polyurethane 20mm
R 0.87
extruded polystyrene 20mm
R 0.71
graphite EPS 20mm
R 0.65
white EPS 20mm
R 0.56
glass wool 20mm
R 0.54
mineral wool 20mm
R 0.5
cellulose 20mm
R 0.48
timber 20mm
R 0.15
plasterboard 20mm
R 0.11
concrete 20mm
R 0.01

How to read this

  • Thermal resistance is the thickness in metres divided by the conductivity. Bigger is better.
  • The U-value adds 0.17 of surface resistance and then flips the total. Smaller is better.
  • Resistances add across layers, so a whole wall is the sum of its parts.
  • Conductivity varies by product; the values here are typical for the material.

Frequently asked questions

Q. What is the R-value of 20 mm of concrete?

0.01 — 20 mm in metres divided by a conductivity of 1.6.

Q. And the U-value?

5.479. That is 0.18 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 109.59 W across 20 degrees.

Q. How much concrete would match it?

0.02 metres.

Q. Which standards does it meet?

At 5.479 it does not clear any of them yet.