Hello Gerd,
completely independent of formal or legal matters, I would strongly advise anyone against doing without an architect. For our construction project, on the one hand, we hired a general contractor and on the other hand, an architect. I must say, the architect was necessary for the following reasons:
1. Because of course he has already drawn thousands of plans and after 30 years of professional experience, he notices things that I do not notice. And for a project for which I will be in debt for 30 years, I don’t want unnecessary annoying corners (you have them anyway, but not so many). Did we think about designing the rooms in such a way that it is possible to live on one floor if necessary? Did we think about enlarging the roof overhang above the front door because it faces west (weather side)?
2. Because our architect could tell us exactly what was not included / still missing in the construction descriptions and offers from the construction companies. For example, we received quotes of around 8,000 euros for the earthworks. Our architect literally tore these apart and then first wrote a proper specification. It then ended up costing twice as much, but we would have been completely taken in by the companies here. In addition, he went through the construction contract with us and pointed out vague formulations to us at dozens of points. He was present at the final contract meeting, which led to these points being formulated concretely.
3. Furthermore: So far around 2,000 euros saved because he called a tiling company regarding “unclean/strange” invoices and settled it.
4. Cost estimates: We would never have factored in 10,000 euros as a buffer for possibly needed additional gravel, 2,500 euros for construction power/water, and many other such points. By the way, neither would the bank, because it is happy about refinancing.
5. Interfaces: How exactly is the staircase attached to the house? Where are the lines to be laid on the building side? How must the excavation be stored during the first earthworks to avoid work and costs later? And how must the substructure of the terrace be prepared so that it can later be built as cheaply as possible and does not have to be connected to the insulation of the house? He took care of these and a hundred other such questions.
6. Furthermore: Experience from over 30 years in the construction business and an independent eye after every relevant construction phase.
Conclusion: The architect will cost us several thousand euros. But we would - although everything is going well with our construction - never save money at this point!