Guide
Concrete wall guideConcrete wall insulation thickness guide
How much insulation a concrete wall needs depends on the target U-value, the wall leaf, and the material lambda.
Used for quick thermal checks of walls, roofs, and floors.
Guide page based on a 25 cm reference wall leaf.
The reference build-up uses a wall leaf, insulation, and finish layers.
The example U-value gives a quick orientation for the guide.
Concrete wall insulation thickness guide worked example
This guide turns the general formula into a wall-specific thickness decision page.
| Layer | Material | Thickness | Lambda | R |
|---|---|---|---|---|
| Layer | Material | Thickness | Lambda | R |
|---|---|---|---|---|
| Interior finish |
Gypsum plaster
Interior finish
|
1.5 cm | 0.700 W/mK | 0.02 m²K/W |
| Structural concrete |
Structural concrete
Slabs and load-bearing elements
|
25 cm | 2.300 W/mK | 0.11 m²K/W |
| Mineral wool |
Mineral wool
General insulation
|
15 cm | 0.035 W/mK | 4.29 m²K/W |
| External finish |
Silicone render
Facade finish
|
1.5 cm | 0.870 W/mK | 0.02 m²K/W |
| Surface resistances | 0.17 m²K/W | |||
| Total resistance | 4.60 m²K/W | |||
How the guide estimate works
R = d / lambda
The guide starts with a base wall, adds insulation, and shows the remaining thermal resistance available for the target U-value.
U = 1 / (Rsi + sum(R layers) + Rse)
That makes the page useful for search, but the calculator remains the right tool for exact project work.
Related wall pages
How To Calculate U Value
Open how to calculate u value for the next step in this journey.
Open next stepInsulation Thickness Calculator
Open insulation thickness calculator for the next step in this journey.
Open supportOpen the calculator
Use the main calculator to edit layers, compare materials, and export a custom result.
Open calculatorR-value vs U-value
Compare the two thermal metrics before choosing a wall or roof build-up.
Open comparisonThis guide helps users compare insulation thickness before finalising the wall design.
The guide is deliberately practical and search-focused so it stays useful on first load.
Use the main calculator to test the exact layer order and project-specific build-up.
The page supports the wider wall content cluster and leads users back to the main calculator.