My statements were not meant to be cruel. If you fixate on something, you ignore the negative aspects. At least that was the impression I had. That's why I tried to take off your rose-colored glasses. At least you should read through the topic of own contribution again in forums. Usually, you don't save that much through your own work due to the extra cost of materials, double burden with rent, double the time compared to a professional, etc. When you then calculate how many hours you have to work to save €20,000, it's quite shocking. A forum can never objectively assess the situation anyway. Only someone on-site can do that. Talk to your bank or financing advisor, speak with an architect, building surveyor, or similar, run through the scenario with the professionals, and then decide.