Construction company wanted in the Stuttgart metropolitan area!

I believe the correct is: Exterior: Ytong aerated concrete [...] Interior load-bearing: Silka calcium silicate brick Interior non-load-bearing: 10cm gypsum wall panels Could that be?

That is a common combination, regarding which I see no reason to advise against it. As far as I know, the manufacturer of this aerated concrete and calcium silicate is the same company, which also suggests proven products for connecting the two parts. Using gypsum wall panels is then technically more harmonious than if you took drywall as a third component here.

Are there major differences in the exterior wall construction regarding heat storage in winter and especially heat retention in summer? I know that the largest part of it comes through the windows, but now only considering the bricks or walls. Are gypsum wallboards as interior walls sufficient for soundproofing, or would [Kalksandsteine] be better here? I just want to avoid hearing every word from the next room or certain noises from the toilet being spread throughout the entire floor.

Are there major differences in the exterior wall structure regarding heat storage in winter and especially heat retention in summer?

The U-value is an absolute factor concerning the overall thermal insulation performance of the wall structure and applies equally to the exchange of heat and cold degrees: thus, the wall with the "better" value slows down the temperature transfer longer. The difference between monolithic and ETICS is how evenly this takes place: with hollow chamber blocks, the transfer speeds alternate rapidly due to the webs and chambers, while with ETICS the more significant part of the slowing occurs along the section with the insulation boards. If you are not professionally involved with physics, you will have to decide based on intuition – for the average common sense of Jane Doe, even the most abstruse arguments from both supporters and opponents usually sound sufficiently plausible.

Are gypsum wall panels sufficient for sound insulation as interior walls, or would sand-lime bricks be better here?

In principle, one can make enough mistakes at component connections that the property differences between two building materials are more than compensated for. The sand-lime brick missionaries will always claim that only their favorite is good enough, but in my opinion, in practice, you won't do worse with gypsum boards. We are talking here explicitly about solid gypsum, not to be confused with gypsum plasterboards on wooden battens (or "more modern" metal profiles). Imagine a 10 cm thick piece of Gouda, chalk-white and roughly concrete-hard (but easier to saw). This interior wall building material is also frequently used in apartment blocks and hospital construction.

Hello , after having followed with great interest for a long time, I would really like to know how you ultimately decided?

Hello , after having followed with great interest for a long time, I would really like to know how you ultimately decided?

Well then, a short update from my side again -> we have made our decision!

Prefabricated house / timber construction

[*]Bittermann & Weiss -> eliminated | Number 1 among prefabricated houses, but we have now decided on a solid construction
[*]Talbau Haus -> eliminated | Reason see below
[*]Hanse Haus -> eliminated | overall impression / gut feeling
[*]Bien-Zenker -> eliminated | due to differences
[*]Fertighaus Weiss -> excluded
[*]Schwabenhaus -> excluded
[*]Albert Haus -> excluded

Solid house providers

[*]Köhler Wildberg -> commitment!
[*]Hauser Massivbau -> eliminated | 2nd place
[*]U-Haus -> eliminated | 3rd place
[*]Haus der Handwerker -> eliminated | overall impression / gut feeling, but was the cheapest offer
[*]AWS -> eliminated | much too expensive
[*]FERMO -> excluded | much too expensive
[*]Härtter Renningen -> no capacity

About Talbau: The initial appointment took place before the Corona crisis, and we had arranged another appointment two weeks later to discuss the offer. Unfortunately, this was exactly the time when contact restrictions and the rapid increase in case numbers occurred. I made all appointments together with my wife so that we both have all the impressions needed for a decision, but a three-person appointment was out of the question at that time. We then asked Talbau for some flexibility and suggested various options (video conference, teleconference, etc.), all of which were rejected. The negative aspect was not the rejection itself, but the unconvincing reasons given. I then asked Talbau for a proposal, and it was: either we meet on-site or postpone the appointment until after Corona. There were a few more statements that I do not want to repeat here, but after that, the matter was closed for us.

Hanse Haus’s houses were quite nice, but in the end, the offer and the building feeling just didn't fit. Also, a coworker is currently building with Hanse Haus and is only moderately satisfied.

I really have to praise Bittermann & Weiss here and mention them positively. I think I wrote something about it a few pages earlier, but the salesperson was very competent and down-to-earth – not the typical salesperson type. We liked their houses the best, and the offer was very detailed and listed every single item. However, we ultimately decided on a solid house. Had we built a prefabricated house, it would have been with Bittermann & Weiss.

I already wrote a bit about AWS; they were simply 50,000 euros more expensive (adjusted for features and services).

I still can't properly classify Haus der Handwerker. The offer was the cheapest of all at a good performance level. The model house was also quite nice and modern. Somehow, though, I had read quite clear negative notes about HdH here in the house building forum and the statements that you have to be more involved in coordination. Also, the free architect design was unfortunately not very good. I know that this is work and that, as in our case, no order came from it, and I appreciate that. But before I make a bad proposal, I prefer to make none. That didn't exactly strengthen my confidence in their abilities for the later house design. ( I am waiting for your comment )

About the Top 3:
U-Haus had a nice contact who put a lot of effort in. The offer was priced in the mid-range, and in the end, it really came down to gut feeling. I can’t really say what the deciding factor was. If there are any questions here, feel free to ask.

Hauser had the best price after HdH and also a really nice contact. You immediately felt well looked after, and everything was discussed thoroughly. Hauser even has the "standard equipment" on display on-site, so you can get an immediate impression. We still find the concept with Liapor prefabricated walls relatively good and could have imagined it. Very positive was also that they questioned the zoning plan and did not just complain about it. There were 1-2 points that from my perspective were not entirely clear, and usually, everyone immediately says "doesn't work," but Hauser said that this should be clarified and tried. A small negative point from my perspective is accessibility, which was not always optimal, and one waited ages for callbacks. But I think they are just currently extremely busy. Thanks for the tip.

At Köhler, the building feeling fit as well. A down-to-earth family business that not only builds houses but also bigger projects. Very nice contact with a lot of experience, and you immediately feel welcome here, too. They took a lot of time in the conversations, even though the order was not yet certain. Köhler comes from structural work and brings a lot of experience from there; additionally, they build a lot in the area and know all relevant local companies as well as contacts at the municipalities. They also speak openly about costs, and contact with other builders is no problem. We both had the feeling that honest and down-to-earth work is still done here and that a lot depends on the customer and his satisfaction. Let's see what the future brings.

Many thanks to for the tip about Köhler, and I will continue to report.

@11ant I am waiting for your comment

You caught me off guard, I don’t currently remember where I might have seen their architects deliver a work sample. But I want to thank you here for your exemplary, differentiated, and transparent presentations of what impression you gained from which provider and why. I find that very valuable for the "readers," but I couldn’t do it myself – simply because I am not currently building and therefore not experiencing this firsthand.