Floor plan of a single-family house measuring 14x14 meters with limited ridge height

Shell construction with roof and windows as well as floor slab, 35 cm envelope like with prefab house manufacturers, without connection costs and groundwork and interior walls only clad on one side. Maybe it helps to imagine the construction costs from the commercial sector, as we adopt several of these elements (sandwich roof panels, load-bearing skeleton, stud construction). I am aware that this construction method is not liked by many and there are disadvantages, which we mitigate as well as possible: stud walls inside double-clad on both sides on a floor slab without screed sound bridge, solar level above the sheet metal roof to alleviate thermal expansion and noise emissions during rain, central ventilation against mold, etc. I have lived for several years in the USA, Iceland, Israel and other countries in houses that were built similarly and found it absolutely okay (apart from the discrepancy between manufacturing costs and selling price of houses in the USA).

It is always a good idea to get inspired by other standards. Skeptics are justified when there are deviations from standards. Those who come with specific pointers instead of general statements usually provide valuable information. It is worth listening and thinking before falling into the reflex of defending oneself. Let me know what it costs. My special attention regarding the construction method you outlined would be on the noise development inside the house - especially the noise transmission from the heat pump and ventilation system. Resonances caused by the building structure are hardly manageable afterwards. Therefore, it is very important to calculate and assemble carefully.

Good point. We had also considered building the room massively out of limestone, but for now we have calculated a wall structure that should also work and meets the requirements (fire resistance, sound). The name of the product is probably not allowed to be mentioned. However, it is a panel material filled with quartz sand.

The misconception here is probably that the OP believes they will save a lot on the shell construction. But that is only one item among many. The interior work is likely to differ little from others. In the end, they have hardly saved anything but have a modest roof with questionable wall construction. We are, however, happy to be convinced otherwise.

Somehow the money issue always seems to be predominant.

That is because we are not discussing castles in the air here.

Somehow the money issue always seems to be predominant.

It is called "House Construction Forum" and not "Graveyard of Broken Dreams".

We have the offer for the shell including the foundation slab of about 180k and yes, there is also an architect contract with 35k. [...] But my concern in this thread was more about the floor plan and ideas that I could contribute to the further planning.

I would not let an architect contract be imposed on me by my construction company, and with an independent architect it is better to first join the discussion without already bringing your own pictorial input.

There are already enough examples here in the forum where forum members have shown that costs of 2-2.5k are plausible if the settings fit: own work, village, enough time, no 0% financing, etc.

In this regard, I recall exactly one point zero examples, namely that of 1200-eur-m.35362/

Shell with roof and windows as well as foundation slab, 35 cm envelope like with prefab house manufacturers, without connection costs and earthworks as well as interior walls only plastered on one side. Maybe it helps to imagine the construction costs from the commercial sector, since we take over numerous of these elements (sandwich roof panels, supporting skeleton, post and beam construction).

In the commercial sector, you are dealing with completely different conditions (not only on the regulatory level). Side glances from the mainstream are basically good, but adaptations from "foreign" areas can also be problematic. My godfather once had a world-famous architecture professor build a building (which works perfectly in desert countries) near the Leonberg triangle (where it encountered physical problems with the climate).

The misconception here is probably that the OP believes they will save a lot on the shell construction. But that is only one item among many. The interior finishing is likely to differ little from others. In the end, they have hardly saved anything but ended up with a modest roof with questionable wall construction. However, we are happy to be convinced otherwise.

Sigh, we are in the forum "Floor Plan Planning / Plot Planning"... We have offers for all trades that are within the regional range and have been confirmed multiple times here in the forum. According to my table, we are currently at ancillary construction costs of 57k and technology/interior finishing of 138k. Additionally, we have planned a 20% buffer and finance only after the shell construction. Yes, a lot of own work is involved and in case of emergency, there is still the option to switch to turnkey, for example, in case of an overseas assignment or similar.

Please be concrete now and say what exactly is questionable about the wall construction? In my opinion, we are already building above the usual prefabricated house standard here (our setup: 12.5 mm drywall, 15 mm OSB, 160 mm wood wool, 15 mm OSB, 12.5 mm drywall). Alternatively, we also had an offer to have the walls cast in expanded glass, but that would be over 40% more expensive and the interior finishing more complicated. The local mason is more committed to Poroton.

And what exactly is modest about the roof? Abroad, that is standard practice and we are at a U-value of about 0.15. Yes, it is a sandwich roof – that may not please everyone in Germany, but it is a compromise that is installed hundreds of thousands of times around the world and works well with the steel beam construction method, since the roof frame is already constructed. According to the roofer, three fields are planned and have already been confirmed by the structural engineer. Yes, I know roofs are subject to temperature fluctuations when exposed to sunlight and then creak, and they also drum in rain. We are risking the life test of whether a large-area solar surface over the roof will mitigate these aspects somewhat, and will gladly report back. In the worst case, it will come off again in a few years and be moved to a farmer’s barn. It should be better than roofing felt, and from the outside, you only see the solar panels anyway.