Bank does not accept own contribution

That's what I mean. These homebuilders take craftsmen without invoices and still get financing. Do they declare own contribution or doesn't the bank ask for invoices?

Yes, and who finances the undeclared work? Fictitious bookings like Wirecard? Or do you have equity in reserve?

You are naive.

I also have a buddy who is booked undeclared. Mainly renovation. I occasionally need his advice, he always complains he has no time. But he also gets paid for his work. He has to make a living after all. By the way, I do not support undeclared work.

Excerpt from the Dr. Klein homepage regarding acceptance of EL:

Banks generally accept up to 15 percent of the loan amount as equity contribution – but usually not more than 30,000 euros. A realistic amount is considered to be between five and ten percent to claim equity contributions in house construction.

By the way, I still have to chuckle about your statement that you don’t need a crane.

so I admire his enthusiasm. And if you really follow through like that, hats off!

Unfortunately, I now also consider it naive. We built a "prefabricated house," only had to do the drywall, painting, and flooring, and only had time on weekends, and I have to say: I've had enough. I want to have time to just "space out" again and not have the construction site in the back of my mind.

My partner is a foreman in civil engineering, his company lent us the necessary machinery for earthworks for free. We did all the earthworks, utility connections, etc., ourselves (we will also do the landscaping ourselves in the future), but we did get quotes from civil engineers and took the lowest one for the bank calculation. Of course, that made us look "worse" to the bank, but we didn't dare declare self-performance because we were afraid that "something could happen" and we would then be dependent on help.

Please provide own contribution

The bank is mainly interested in the construction progress. The architect can confirm that. Then there is money. In case of doubt, you must pre-finance the illegal worker from additional equity.

The company Freitag und Schwarz has always been something you had to be able to afford, cash without a bank and without warranty.

You build a house completely without warranty claims and the bank has to liquidate it in case X.

In short
100% financing
built by amateurs
without warranty claims
with the risk that it won't be finished
in doubt, at the time of liquidation there is an unfinished house with significant construction defects and piles of worthless building materials.

Deal with the topic of Ausbauhaus. That reduces the bank's risk and they are known concepts.

I have looked into Ausbauhaus. You are partly limited in the floor plan and finding the non-black sheep among the providers seems to be a task. Where is the big difference? Just in the shell and windows? The rest still has to be fully taken over, right?

Not 100% financing, but about 80%. Also significantly less capital given out because less is needed (since labor costs are saved). I know of a villa around here that is half finished and building materials are lying around. It is very individual and will not be sold quickly. A bank lost more money there than if my house ended up at 0 EUR. I want to say that there are other reasons besides self-construction that cause problems (bankruptcy of the construction company, subcontractors in jail for social fraud, and so on).

By the way, I still have to smile about your statement that you don’t need a crane

Why would I need a crane? The side components weigh a maximum of 300kg, probably closer to 200kg. The plan is a rope hoist and three people for erection.
The roof beams are supposed to be placed on scaffolding upon delivery. Since I want a light roof, I don’t need such a high cross-section and therefore less weight. If the architect and structural engineer approve, I would even forgo beams and nail planks together (typical American construction method) to achieve the necessary strength.
Where else would a crane be needed?