Scaling of construction costs or how much does one more square meter cost?

The crux of the matter is that the assumed average value depends on various factors and is not set in stone. Moreover, in my opinion, it only allows for a rough estimate of the later costs. However, that is still better than being completely in the dark.

Hello,

What do "2-3 planings" mean to you? 2-3 drawings and it has to "fit"? Or is one planning divided again into phases?

What happens when you go to the architect? You get to know him, look at his work, possibly finished houses, and then you have to decide whether you want to plan your house with him. If the architect is a smart guy, he will even work out a first draft for you free of charge. But at the latest then you face the question: contract (LP from-to) yes/no.

We currently have a case where both partners of the potential builders work more abroad than a reasonable scheduling would be possible. Thus, so far, much has been done by e-mail and telephone; which – as has once again proven – is not the best prerequisite for the design planning. 3 planings were therefore already for the proverbial trash. For different reasons, but mostly because both partners have contradictory ideas about the house. 8 days ago, both were in Germany at the same time, so we could attend a joint appointment with our architect. In the conversation, the particularities of the plot as well as the – opposing – wishes of the clients were clearly communicated and a compromise of tastes was sought. Based on this, the 4th and provisional last planning is currently being created. If it – from the clients’ point of view – does not reflect the implementation of their ideas, a planning contract will be concluded or we part ways amicably.

On average, I can state that 2 complete design planings lead to the goal ;)

Rhenish greetings

It's actually sad in the industry. Other professional groups do not pick up the pen before the contract is signed.

Not even within the industry.

Let's assume I had an offer for a house with 200m² living space for €400,000.

It depends on what is included in the €400,000. Subtract the additional construction costs and all other extras (garage, ...). For example, €400,000 minus €30,000 additional construction costs equals €370,000. You then scale this amount to the new square footage. This will probably fit well if there are no other significant changes.