Bank does not accept own contribution

Or does it always come down to this formula: building a house yourself as a non-professional = entirely equity? That shouldn't be the case, I think.

Your skills can be masterful and your time budget large. That doesn’t count for the bank. They have experience values and don’t credit you with a bonus.

It would be worth trying to make a detailed project plan, listing costs and hours of your own work, integrating these into the external services, and showing why you can spend enough time on it and who could help in case of a Plan B. Also include references of your own craftsmanship – which projects have you already done? Experience counts. The bank needs security and trust. Such a plan is a trust-building measure.

In case of forced sale of the house, the bank wants to get its money back. For that, the house must have an appropriate value. This assessment is different when done by construction companies than by a self-builder. A guarantee from a solvent third party would help.

I am looking forward to the construction diary. Please link it here

Not like this goes:
Day 1-Day 30: Full of anticipation I go to the construction site and am fully convinced that I will manage the project within the planned time.

Day 30-60: Well, back to the construction site. Whatever, project is running as planned +2-6 months.

Day 61-xxx: If I had known that, I would never have wanted to build this damn house myself. Every day on this damn construction site. I’m really fed up. Why didn’t anyone in the house-building forum warn me???

Keeping my fingers crossed for you.

...I would try the bank that has "always" known me.

What you say about financing – and here equity is a blind spot on the map – is true, but I have also seen horses puke. First explore, then see further. He can always still leave it at that. A guarantee definitely helps, just not the guarantor.

I wish the homebuilder a good decision, whatever it may look like.

Best regards Gabriele