ᐅ Wall construction for KfW 40 standard (monolithic or with external thermal insulation composite system) for a single-family house

Created on: 24 Dec 2025 06:44
M
Markusba
M
Markusba
24 Dec 2025 06:44
Hello experts,
with our new bungalow construction project, we are still undecided about the wall structure (here only wall structure for KFW40).
Originally, we were planning: Poroton + ETICS (external thermal insulation composite system). After initial discussions with the shell builder, he recommended considering a monolithic wall structure.

Therefore, I would be interested in your opinions on this.
The U-value is almost identical; the costs seem to be slightly lower for the monolithic structure (prices are from websites: hopefully they are somewhat accurate!).
In single-family house construction, I mostly see a monolithic wall structure.

Thank you 🙂










































Poroton T16 42.5cm (17 inches) + Hasit 242 (light plaster)
Poroton T14 24cm (9.5 inches) + EPS 20cm (8 inches)

U-value W/(m²K)
0.13
0.12
Material costs /m² 160€ for Poroton + 30€ for mortar (60€ for Poroton + 30€ for mortar) + (30€ EPS + 30€ mortar)
Labor costs /m² 80€ for Poroton 80€ for Poroton + 70€ for EPS
Total 270€/m² 300€/m²
Advantages - higher sound insulation
- simpler construction (fewer trades involved) → less prone to errors
- lower tendency for algae/mold growth
- easier connections (windows, etc.)
- easier to plaster
- more impact resistant
- better thermal insulation
e.g. from Schlagmann or Wienerberger including a good range such as load-bearing insulation, window fastening reinforcement)
M
Markusba
24 Dec 2025 07:08
oh sorry it is a T6 with perlite (not T16)
Nida35a24 Dec 2025 08:23
We have a bungalow made of expanded clay aggregate blocks (Liaplan), monolithic, plastered inside and outside, 42cm (17 inches) thick, without KFW certification, but performing better in calculations than KFW40.
11ant24 Dec 2025 10:14
Markusba schrieb:

After initial discussions with the structural builder, he recommended considering a monolithic wall construction.

I have nothing to add to my stone mantra; it remains valid unchanged.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
Y
ypg
25 Dec 2025 10:18
I would no longer choose to use external thermal insulation composite systems (ETICS) voluntarily if there are other options available.
N
nordanney
25 Dec 2025 11:37
Markusba schrieb:

So I would be interested to hear your opinions on this.
I don’t really care about the wall construction itself. What matters is the final result. (If I had to choose, I would rank cavity walls, monolithic construction, and then ETICS in that order. If price were the factor, it would be exactly the other way around. My recent houses were brick veneer, brick veneer, and currently ETICS—but with rigid phenolic insulation because it doesn’t require such thickness.)

And the prices you mentioned can be ignored. It’s the internet and has little to do with real prices. If your shell builder, who normally constructs monolithic walls, has to hire a team specialized in ETICS, it will be more expensive (and more prone to errors). And vice versa.

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