Construction costs mini-bungalow (approx. 50m²)

The bathroom - completely cast from plastic (?) -

Yes, I know that, like back then in the student dormitory
TE, don’t think for others, especially not about what could happen if a woman joins. A woman could surprise you, for example, by not wanting to move in at all, but rather preferring to create/find something of her own together. "One" doesn’t just want a drawer or a corner for their stuff, but maybe brings their own furniture, so where does that go? Maybe hobbies too, then 50 m2 isn’t much and 100 already feels tight if the man has already taken up space. We have 200 m2 for two and I have space problems... well, it’s also partly still a construction site. So I would first look at what is actually needed or desired, and I simply guess that the effort (also regarding costs) for 100 m2 is not much higher than for 65 m2, since some items are simply there and do not decrease proportionally to the house size. And then reconsider whether 100 m2 might be better, especially you can sell such a house more easily if a woman joins who wants something "of her own". Or put a mobile home on the property? Definitely stay flexible.

First of all, thank you for your numerous responses.

Inspired by the post about the Olympiadorf, I sat down and designed an extreme downsizing variant of my bungalow based on the downsizing version. However, I must say that with such small buildings, every further reduction involves a significant compromise. I have reached a living area of 40 m² and would hardly find space to dry laundry in the winter. In summer, it's no problem at all; in winter, you have to make yourself comfortable in the armchair with the drying rack right next to it. The space for cabinets is then also very limited, see picture.

No problem at all in summer, in winter you have to make yourself comfortable on the armchair, with the clothes drying rack right next to it

That's how it is. Apart from the bathroom here, which could still be reduced somewhat, the ratio of required space to leisure space becomes increasingly unfavorable the smaller the living unit gets. Restrictions are felt more strongly the longer the exposure time. As a rule of thumb, I would say comfortable living requires one square meter per person for each week of the year in which living takes place (thus certainly less for a holiday or weekend home), plus a 20 to 25% surcharge for each additional person.

Imagine a big caravan, with that you are still flexible and can even go on vacation with your "home."

I have spent quite a long time dealing with so-called "Tiny Houses" myself, as I didn’t want to pay rent from after university until the "real house purchase." Everything turned out differently than planned, since it didn’t actually go to Hamburg, but whatever.

There are many providers of small and modular houses. The latter were an option for me, as they can be moved and combined at any time. My idea back then was to buy one module and later place it on a solid structure. Depending on the provider, this works with more or less effort and costs. In any case, you can find many good floor plans on the websites; a tiny house only works if the planning is 100% correct. So it is considerably more demanding for an architect.

A proper "Tiny House community" does not really exist, but the Stover Strand campsite basically consists only of mobile homes, some modern and of good build quality, others still those old plastic ones from Holland. The owner is officially trying to obtain building rights for a Tiny House community on his campsite – whether that works is another question.

And to be honest, I don’t think RobsonMKK’s idea is completely stupid either, even if it might not have been meant seriously – it would just be too small for me, unless I were a student constantly changing residence. Beyond a certain size, a truck driver’s license is also required. A module could later also be used as a holiday home or rented out – of course, you would need land for that again.

Banks really are reluctant to finance very small houses or modules. The lending value is very difficult to determine, as the target group and thus the marketability are very hard to calculate or essentially non-existent. However, for a small amount, a "normal" loan might also be possible without generating exorbitantly high interest costs, or the lending value of the land minus demolition costs might be sufficient.

However:
The cost savings when building 50 sqm instead of 100 sqm are probably not as high as you wish. In addition, unlike in an apartment, the heating/technical equipment must also be accommodated; where are the clothes supposed to dry? Where do the motorcycle gear and so on go? Although I really like tiny houses, under 75 sqm would not be reasonable for me in terms of space and economically.

(as a student, with an appropriate campsite nearby (like it was at my place of study), I would buy a tiny house like the one below, nowadays there are several German providers of these originally American "houses," and then start a Europe tour with it. Afterwards, rent it out or something – by then, the house would have paid off anyway
)

However: The cost savings of building 50 sqm instead of 100 sqm is probably not as high as you wish. Also, unlike an apartment, the heating/technical equipment must be housed somewhere too, where does the laundry go to dry? Where do the motorcycle gear and so on go? Although I really like tiny houses, for me anything under 75 sqm wouldn't make sense in terms of space and economics.

I’d say, a 50 sqm house instead of 100 sqm is fifty percent less house for ten percent less price. And this "saving" will later be absorbed again if you expand to "full size."

It is better to plan "modularly" in the sense that you first fully finish only half the house.