Cost of foundation/basement for wooden house

Hello forum,

we are planning to build a prefabricated wooden house (9 cm log walls) with the following dimensions:

Step by step, we would like to upgrade it (sanitary facilities, reinforced roof, and of course insulation/external cladding).
In addition, a foundation would have to be built in the first step. Now the question came up whether it would be possible to invest in a basement right away and how much that would cost? The background is that the space is quite limited at about 60 sqm. With a basement, you would gain some space and have a room for electricity/water connections.
The questions now would be:
- How much does just the foundation cost?
- How much does a basement with about 15 sqm (preferably under the room with 28.53 sqm) + foundation cost?
- What do you think of the plan in general?

We would be very grateful for assessments.

Best regards

What use is the house intended for?

: Initially as a weekend house/guest house. Later possibly also permanently, but for that of course insulation etc. would have to be installed first.

In general, we would of course also be interested in the experiences/assessments of the forum regarding the use of the house. As mentioned, we would use 90mm beams, then insulate with glass wool and clad from the outside. The floor and the roof as well. Do you see the feasibility of an energy certificate here?

-What do you generally think of the plan?

Distance.

We regularly have bold smart alecks here who plan on the module house / tiny house track or something similar, in a piecemeal manner or with growth rings little by little to build a permanent residential building in the medium term. And it repeatedly fails because of the same regulatory reality that opposes such nonsense ideas:

A residential building is a residential building. For its approval, among other things, it must comply with thermal insulation regulations, from which there is no discount just because year-round occupancy is not planned in the foreseeable future. Also, you could remove the back seat from your car, but that wouldn’t reduce its consumption: the same applies to the costs of house connections, which are the same for a weekend house as for a year-round family apartment. The chimney sweep comes just as often for inspection appointments, and nothing scales down here otherwise. Therefore, it's better to buy a proper car right away than to build a soapbox car, and it’s the same story with the basement: it won’t be any cheaper than a normally sized full basement, which is just depressing.

: Thank you for your extremely kind feedback! It could certainly be a catch to get an energy certificate. However, the manufacturer also offers insulation packages directly. I also have no concerns about insulating the house all at once. Whether it will be approved remains to be seen. In any case, we believe that it is the right plan. We would, as mentioned, initially use it as a weekend house, so costs do play a role. The basement can be omitted. However, we definitely like the style of the house. Therefore, we would be very grateful for further experiences with such log houses. When you search on the internet, you find many interesting posts.