Insulation·plasterboard 400mm
plasterboard · 400mm
R 2.22
U 0.418 W/m²·K

plasterboard, 400 mm — R 2.22

400 mm divided by a conductivity of 0.18 gives an R-value of 2.22. The U-value is 0.418, so a square metre leaks 8.36 W across a 20-degree difference.

Standards it meets

Not up to any of them yet

Material
plasterboard
Thickness
400 mm
Thermal conductivity
0.18 W/m·K
Thermal resistance
2.22 m²·K/W
U-value
0.418 W/m²·K
Heat lost per square metre
8.36 W
As concrete
3.56 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 panel16 mm
  • phenolic foam44 mm
  • rigid polyurethane51 mm
  • extruded polystyrene62 mm
  • graphite EPS69 mm
  • white EPS80 mm
  • glass wool82 mm
  • mineral wool89 mm
  • cellulose93 mm
  • timber289 mm
  • concrete3556 mm

Nearby cells

plasterboard 300mm
R 1.67
timber 400mm
R 3.08
concrete 400mm
R 0.25

Same material, other thicknesses

plasterboard 10mm
R 0.06
plasterboard 20mm
R 0.11
plasterboard 30mm
R 0.17
plasterboard 50mm
R 0.28
plasterboard 70mm
R 0.39
plasterboard 100mm
R 0.56
plasterboard 120mm
R 0.67
plasterboard 150mm
R 0.83
plasterboard 200mm
R 1.11
plasterboard 250mm
R 1.39
plasterboard 300mm
R 1.67
plasterboard 400mm
R 2.22

Same thickness, other materials

vacuum panel 400mm
R 57.14
phenolic foam 400mm
R 20
rigid polyurethane 400mm
R 17.39
extruded polystyrene 400mm
R 14.29
graphite EPS 400mm
R 12.9
white EPS 400mm
R 11.11
glass wool 400mm
R 10.81
mineral wool 400mm
R 10
cellulose 400mm
R 9.52
timber 400mm
R 3.08
plasterboard 400mm
R 2.22
concrete 400mm
R 0.25

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 400 mm of plasterboard?

2.22 — 400 mm in metres divided by a conductivity of 0.18.

Q. And the U-value?

0.418. That is 2.39 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 8.36 W across 20 degrees.

Q. How much concrete would match it?

3.56 metres.

Q. Which standards does it meet?

At 0.418 it does not clear any of them yet.