ᐅ An above-ground basement?

Hello everyone,

So far, I have only been reading along in the forum and found a lot of interesting information.

Now I am planning to build a single-family house.

I am surprised that there is so little information about concrete in private construction, even though in real life I have already seen several architect-designed houses made of exposed concrete. I don’t want or am allowed to build something that extreme, but I am interested in whether the cost-effective construction method of a basement can also be used above ground for living spaces. Manufacturers of prefabricated basements advertise how versatile their products are. But is it really possible to build something other than a basement this way?

Does anyone have experience with KFW-55 compliant concrete walls for the ground floor of a single-family house (essentially an above-ground living basement)? Does this work in practice?

Thanks in advance for all your answers!

p.s.

Please, let’s not discuss breathable versus non-breathable walls in this thread. Thank you.

Also, I am aware that installing electrical wiring inside concrete walls is quite complicated. However, this can largely be avoided through design by placing installations, light switches, etc., in drywall interior walls. Theoretically.

Of course, you can build entire buildings like that. If you want exposed concrete, the question is how you plan to install the insulation. Basement builders also offer insulation integrated into the shell, which would probably be sufficient at least for the parts in contact with the ground. Achieving KfW 55 standard for the exterior wall against air infiltration would, however, be more challenging.

Thank you for your reply. No, I do not want exposed concrete and I probably wouldn’t be allowed to build it either. I am indifferent regarding the type of insulation – whether inside or outside doesn’t matter to me; the real question is whether the insulation is sufficient to prevent air leakage for KfW-55. If using an external thermal insulation composite system (ETICS / WDVS), it should theoretically be possible with enough thickness.

The real question is whether you are willing to pay for it.

Whether you build your ground floor with concrete and external thermal insulation composite system (ETICS) or with calcium silicate blocks and ETICS, it is technically almost the same. In the end, nobody wants to cover the costs.

bindig schrieb:
I find it surprising that there is so little information about concrete in the private housing sector, even though I have personally seen several architect-designed houses made of exposed concrete.

My recommended reading here would be https://www.hausbau-forum.de/threads/hausbau-aus-beton-vs-Energieeinsparverordnung-2016.23880/ and https://www.hausbau-forum.de/threads/wdvs-mit-betonbau-oder-sichtbeton.24121/

Specialists in basement construction are familiar with earth pressure and groundwater, but usually less so with architecture, and above ground it should probably look somewhat attractive as well, right?

---

https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

@11ant: Thanks for the suggestions. Appearance is not that important to me. I’m not allowed to do a concrete look anyway: I will most likely have to build a one-and-a-half-story house with white plaster and a red or black pitched roof.

My original idea was similar to this:

Thousands of homeowners build basements using concrete sandwich panels (just take a look at the precast basement manufacturers). In principle, this could also be done above ground.

But the linked argument

Sandwich construction is more suitable for multi-family buildings; for single-unit projects, the costs for designing each individual panel with its built-in components and openings, as well as the setup costs for formwork, are disproportionately high (both absolutely and compared to material production costs).

makes sense to me.

And also

It is also possible to replace the in-situ concrete layer with an insulation layer, so that you have concrete on both exterior surfaces. However, then the inner shell cannot be designed as a thin "lost formwork," but must structurally replace the in-situ concrete layer from the previously described variant. Therefore, it is considerably heavier, which affects transportation logistics and possible panel dimensions.

The linked threads also mention 60 cm (24 inches) of insulating concrete. Maybe I’m being a bit irrational here. I’ve already planned 50 cm (20 inches) wall thickness in my current layout for solid masonry. But more than 50 cm (20 inches) is beyond my acceptable threshold.