How do I go about house planning?

Hello. We would like to build new and apply for a plot of land but don’t know how to plan in order to also present a realistic calculation to the bank. We are from Bavaria and have read that the prices here are calculated higher. How did you do it? Initially request turnkey companies? What I should also add is that throughout the entire development area only FD Max 5 degrees are allowed, so a Kobus house, which now also gives me headaches because I originally calculated with normal m2 at 2500.- and now don’t know if that isn’t much more expensive. Does anyone from the area have experience with the prices or can name companies that can help me plan properly? Have a nice evening

Where exactly is the "area"? The district of Bad Kissingen, for example, has very different prices than Starnberg.

Is the property firmly committed or purchased?

An FD with 5° can still be called a shed roof; it just needs a waterproof sub-roof, but the water can still drain. And so the shed roof is actually the cheapest roof type overall. Unlike the real flat roof, by the way, which is rather an expensive roof type.

An FD with 5° can still be called a shed roof; it just needs a waterproof underroof, and water can still drain off. And so the shed roof is actually the cheapest roof type overall. Unlike the real flat roof, by the way, which is rather an expensive roof type.

No, a cube/flat roof often has this slope. Nevertheless, it is still called a flat roof. But whatever. Flat roofs are no longer a cost factor nowadays.

I assume you have already tested your limit at the bank?
I would visit a nearby builder and ask how much a cube with 160 sqm according to the Energy Saving Ordinance costs with them. Heinz von Heiden, Schwörerhaus, they all have that type of house in cube form. Then plan at least 50,000 extra for furnishings. Then painting and flooring with 20,000. Additional building costs with at least 30,000. Better 50,000. It could be rocky ground. A soil survey would of course be great to have done before purchasing.
So you need: plot and purchase incidental costs
House e.g. 150 sqm x 2200 = 330,000
50,000 mentioned furnishings
50,000 additional building costs
20,000 floors etc.
25,000 garage and co.
25,000 outdoor facilities
15,000 kitchen
All estimated for 2022
If the bank gives its OK, then planning begins, going to builders and home builders...

A precise calculation is usually required but results from the planning.
P.S. Turnkey houses are hardly a thing. Often the painting work has to be organized yourself. Kitchen too. Etc.
At 2,500/sqm you are well positioned. But that is only for the house. No outdoor facilities, no additional building costs.

Flat roofs are not noticeably more expensive than gable roofs. And just as ypg wrote, they are mostly flat-sloped, i.e. up to 5-10 degrees. However, they are not shed roofs.

Flat roofs are not noticeably more expensive than gable roofs. And as ypg wrote, they are mostly flat-sloped, i.e. up to 5-10 degrees. However, they are not shed roofs.

I think I have often read that flat roofs with a slight slope are the cheapest type of roof. Am I mistaken? I'll look it up...

I think I’ve read several times that flat roofs with a slight pitch are the cheapest type of roof. Am I mistaken? I’ll look it up...

That certainly depends on the starting point and where you want to go when you talk about "more expensive." More expensive than what?

If you build a wooden beam ceiling with a gable roof above it and want to switch to a flat concrete roof, that could be more expensive. If the flat roof is supposed to be made of wood, it could be cheaper because you save the entire roof truss, a hatch, possibly windows. Instead, the wooden beam ceiling is insulated more strongly and a waterproofing layer is applied.
This construction is inexpensive, yet not recommended. Nowadays, I would neither use wood nor mineral wool on a flat roof. The damage potential is too high if a leak occurs.