Is it possible to found a single-family house without concrete and earthworks?

Caravan would be easiest

Ask me who is supposed to approve that where and who is going to provide financing for it, take out building insurance, etc.

Ecologically correct would be not to build new at all, but to acquire an existing property.

The tire foundations should be stable in permafrost. If you build directly on the ground, the houses will sink.

I think with the building regulations in Germany, something like that would not be approved.

Ecologically, existing buildings are preferable, and if something is broken, it should be replaced with building materials without pollutants from regional production.

Are car tires really that ecological? [emoji848]

I also consider it most ecological to buy an existing property of appropriate size.

How are the mobile homes from Schwörerhaus for example founded?

There will be neither approval nor funding for something like this. Save your lifetime researching this.

What a crazy idea

on a point foundation - living area 43sqm