Smallest possible "mini-house" for residence

Anyway. Basically, a porta-potty is sufficient for a registration address.

You really are a hero.

An apartment within the meaning of this law is any enclosed space used for living or sleeping. Accommodation on board a naval ship also counts as an apartment. Caravans and houseboats are only considered apartments if they are not or only occasionally moved.

I read something about living and sleeping. Sure, you can sleep standing up in the porta-potty. Or also sit and work with your laptop on your lap while shitting...
By the way, a houseboat is not a yacht; houseboats are watercraft designed as homes, like floating houses.

And if it becomes a caravan, building regulations must also be observed (provided they are even allowed in the municipality). Whether it is the paved pitch, boundary and light rights/regulations, building classification as a structure (Building Energy Act/Energy Saving Ordinance). Oh yes, electricity and water are also needed.

==> According to prevailing legal opinion, the "permanent," "long-lasting," or "regularly recurring" placement and use of a caravan on the same property constitutes a "predominantly fixed use" within the meaning of building law.

This has the consequence that the caravan could be classified as a "building structure" and consequently subject to approval.

No, we are talking here about a residential building plot, which in turn allows approval-free construction measures. This also includes a caravan.

A caravan in the outdoor area §s35 Building Code is something completely different. In the indoor area §34, I can basically do whatever I want. Of course, within the framework of the building regulations of the respective federal state.

Garages up to 50 sqm, buildings with fireplaces up to 10 sqm, greenhouses, etc., are to be constructed in the approval-free procedure.
Just like a portable toilet.

But always dependent on the building regulations of the respective federal state, there are significant differences here. The East German federal states are much more relaxed and liberal here than those of BaWü.

No, we are talking here about a residential building plot, which in turn allows for construction measures exempt from approval. This also includes a caravan.

A caravan in the outside area §35 Building Code is something completely different. In the inside area §34, I can basically do whatever I want. Of course, within the framework of the building regulations of the respective federal state.

Garages up to 50 sqm, buildings with a fireplace up to 10 sqm, greenhouses, etc., are to be erected in an approval-free procedure. Just like a porta-potty.

But always depending on the building regulations of the respective federal state, where there are significant differences. The East German federal states are noticeably more relaxed and liberal here than BaWü.

Of course you can build something like that. But you are not allowed to live in the garage! And that is what it’s about. Question of the OP understood? He wants to have a residential house with a registered address (however "residential house" is then defined or implemented). You can live in the greenhouse if you want.

Aside from that, the requirements of the Energy Saving Ordinance or now the Building Energy Act apply to RESIDENTIAL BUILDINGS – regardless of whether approval is required or not. And then we come back to the registration system – you need an apartment to register. An apartment is in the residential building (for me also in the caravan, which then becomes a residential building in terms of building law). And for that, you need the Energy Saving Ordinance / Building Energy Act for new construction.

Therefore, your post is completely meaningless, as it has absolutely nothing to do with the question.

With Pampa I rather mean a village of about 300 inhabitants somewhere at the end of the world.

If there is a building plot there, it may be cheap, but driving to the ass of the world to wash laundry is probably a bit too "unrealistic" to implement. In addition, the infrastructure and ancillary costs are uneconomical. Basically, your wishes go towards a camper for a camper, only with a fixed water connection. You can't call it a house. Mobile home fits better (already mentioned), where you can also register your secondary residence on the corresponding leased land. Otherwise, I would say: Your idea reads like "I want to drink milk every day, now looking for a pasture for a new cow."

You absolutely have to tell more about this paradise.

In our area there are settlements in forests everywhere: formerly holiday homes, nowadays most of them expandable and approved for permanent residence. Example: Immonet no.: 46843633, Immonet no.: 47051612, Immonet no.: 46870216 (our local area is currently swept clean or nothing in the offers)