Insulation·timber 70mm
timber · 70mm
R 0.54
U 1.412 W/m²·K

timber, 70 mm — R 0.54

70 mm divided by a conductivity of 0.13 gives an R-value of 0.54. The U-value is 1.412, so a square metre leaks 28.23 W across a 20-degree difference.

Standards it meets

Not up to any of them yet

Material
timber
Thickness
70 mm
Thermal conductivity
0.13 W/m·K
Thermal resistance
0.54 m²·K/W
U-value
1.412 W/m²·K
Heat lost per square metre
28.23 W
As concrete
0.86 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 panel4 mm
  • phenolic foam11 mm
  • rigid polyurethane12 mm
  • extruded polystyrene15 mm
  • graphite EPS17 mm
  • white EPS19 mm
  • glass wool20 mm
  • mineral wool22 mm
  • cellulose23 mm
  • plasterboard97 mm
  • concrete862 mm

Nearby cells

timber 50mm
R 0.38
timber 100mm
R 0.77
cellulose 70mm
R 1.67
plasterboard 70mm
R 0.39

Same material, other thicknesses

timber 10mm
R 0.08
timber 20mm
R 0.15
timber 30mm
R 0.23
timber 50mm
R 0.38
timber 70mm
R 0.54
timber 100mm
R 0.77
timber 120mm
R 0.92
timber 150mm
R 1.15
timber 200mm
R 1.54
timber 250mm
R 1.92
timber 300mm
R 2.31
timber 400mm
R 3.08

Same thickness, other materials

vacuum panel 70mm
R 10
phenolic foam 70mm
R 3.5
rigid polyurethane 70mm
R 3.04
extruded polystyrene 70mm
R 2.5
graphite EPS 70mm
R 2.26
white EPS 70mm
R 1.94
glass wool 70mm
R 1.89
mineral wool 70mm
R 1.75
cellulose 70mm
R 1.67
timber 70mm
R 0.54
plasterboard 70mm
R 0.39
concrete 70mm
R 0.04

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 70 mm of timber?

0.54 — 70 mm in metres divided by a conductivity of 0.13.

Q. And the U-value?

1.412. That is 0.71 — the resistance plus 0.17 of surface — turned upside down, and a square metre leaks 28.23 W across 20 degrees.

Q. How much concrete would match it?

0.86 metres.

Q. Which standards does it meet?

At 1.412 it does not clear any of them yet.