Question about a plot with location plan

The building window is the black line with the dots, right?

That is the building boundary; correct.

How can I see how long the house may be in total? And is it allowed to extend laterally beyond 8.50 meters through a bay window, or can it be at most 8.5 meters wide everywhere?

All of that is stated in the development plan, respectively in the textual stipulations for the property; if it is permitted. Why don’t you finally find an advisor you trust? Trying to save at the wrong end is always bad advice! Many of your questions are not that easy to answer, or you’re simply unlucky that Dirk or other experts are not online! Rhineland greetings

What are the purchase prices per sqm with you? 370sqm is really a joke. The 3-meter dimension to the neighbor is certainly not applied everywhere for fun. So the house may be 8.5m wide. The length will probably be around 12-14 meters. So you won't get a bungalow on there :) The development plan will certainly specify what you are allowed to build on it.

370sqm is really a joke.

Only someone with too much time can write that :rolleyes: Rhineland greetings

A joke too expensive or too cheap? You just can't say that so easily nowadays :)

The building envelope is the black line with the dots, right? How can I see how long the house is allowed to be overall?

If it's not stated anywhere in the development plan, I would roughly calculate the lengths by using a ruler over 3 sentences. In my opinion, the important thing with such small plots is how much may actually be built over.

Or how can you be sure before buying that you can do what you have planned?

Everything is stated in the development plan. In case of uncertainty, an architect can help.