Planning a land purchase and a 400k budget for house construction

Do you think the project without a basement is as feasible as shown in the drawing?

You have not founded frost-deep on the valley side, but only 30 cm deep – otherwise, I think it should be doable. A height difference of 130 cm under the base area means, according to my basement rule, an effort of 70% of the basement costs.

Our architect had this crazy idea too: "lost masonry." However, in our case, it was almost a full story height and about 8x15m floor area. Two years ago, in a rather affordable area, this nonsense was supposed to cost 60K€. A full basement was 20K€ more expensive. The saved floor space in the ground floor for the technical room alone already justified the extra costs. Now, in your case, it’s not a full story height, but the costs will still be considerable. A full basement, leaving out the attic, and making the whole house taller (entrance at ground floor, basement then half living space, half basement) is the better option.

Now it is not a full floor height for you, but the costs will still be considerable.

I’m telling you, seventy percent (for a zero basement), a 50% partial basement would come to seventy-five. The twenty-five points "more" for a full basement are then practically no additional cost in net terms if you offset the attic that can be saved.

Thanks first of all.

At the moment we are renting in a new development area and I asked around a bit in the neighborhood.

Right next to us, on an area of 10x8m (approx. half of our project), a height of 1.30 had to be leveled, for example. And he tells me something about 12k, I always wonder about that then.

In that case, it would almost be worth it (purely from a monetary point of view).
We just wanted to stay above ground.

No idea what the 12K refer to. For us, as mentioned, it would have been a full story height, and at least there, the layer-by-layer compaction, resisting earth pressure using earth pressure beams, drainage for hillside water, etc. were considerably more expensive. Even if it would be cheaper for you: you then have to provide a technical room on the ground floor as well as an attic - both of which are unnecessary if you cleverly integrate a basement with partial living space. Apart from that, what are you going to do with the height difference to the terrain in the current version? The patio doors would then be about 1.6m too high. You have to deal with that somehow (balcony, stairs, or filling up), which of course also costs money. Next point: 15% or 1m slope towards the house is actually not a very good idea if you think about a heavy rainfall... especially not with timber frame construction. That would also need to be taken into account, again for some small change. Of course, you should stay above ground: basement/cellar raises the ground floor and entrance to street level (possibly slightly above). The basement is a cellar in the direction of the slope, living space towards the valley. The attic is omitted.

So the 12k referred to the neighbor for fill material + pipe installation + compaction. That was also stated in his offer or invoice. That was also what I observed being done there during the day. Whether this is good for the future in terms of settling and everything, I’ll leave undecided. Your version definitely sounds plausible. Regarding the terrace and carport, both the right and left sides of the house should be filled and compacted to the same height as for the floor slab, so that you are more or less at the same height as the house. If we go with basement/lower ground floor and ground floor, we would have to completely redesign and possibly also switch to solid construction, since basement + prefab bungalow according to my research would then be more expensive.