Enlarge and fully renovate a single-family house or demolish and rebuild?

Which program can I use to do it?

Tell me which one you use?

I'm already trying my best to make it at least somewhat imaginable.

Then scan the development plan that the draftswoman showed you. Then the people here who can read something like that will see what is possible and what isn't. It seems to me that you are giving up too soon.

Which one do you use it with?

Then scan the development plan that the draftsman showed you. Then the people here who can read such things can see what is possible and what is not. It seems to me you are giving up too early.

I use paint.net.

So that means I just draw a few lines back and forth. But I'm currently redrawing the plan with the correct wall thicknesses!

Attached is the development plan!

Attached is the development plan!

Should it be house no. 5 / parcel 123? - that is way too little of the plan. Tell me its name (without a link!, or email it to me, see forum search "11ant gmx"), without the "textual specifications" one can say little.

I am doing it with paint.net. So that means I just drag a few lines back and forth. But I’m currently redrawing the plan, with the correct wall thicknesses!

That won't work. Paint(net) has no ruler or background grid, you can't position anything properly. In e.g. Open Office that works much better. Or you take hobby planner's favorite "Sweet Home 3D". In any case, don't fuss over too exact dimensions: it's enough if you redraw the walls 36.5 / 24 / 11.5 as 40/20/10 cm and also round the rooms in between to the nearest 10 cm. And get a proper scanner going or at least hold the camera straight above it.

Here you go, your email has arrived and I have looked at the development plan. This was established in 1976 and became legally binding in 1979. At that time, your house was already standing and was therefore incorporated into the plan as an existing structure, which is why the building envelope starts at each house at the street-facing front (plot-specific, since it is not the same but only similar for the neighbors) and extends 14 meters deep from there. For some garages, this means that they would require an exemption if rebuilt in the same location because they are too long. The roof pitch is 48° with a +/- 2° tolerance. The neighboring houses 9 and 11 have individual small shed dormers, apparently the only ones in this section according to the aerial image. I must withdraw my suggestion of the wide shed dormer because requests for exceptions of this extent are apparently not common in this area, and I therefore see little chance for them. Already the "dormer" in the picture of post #51 would, in my opinion, be a precedent in this planning area. At least in this section, no ridge direction is prescribed. Despite no specified heights, I see no worthwhile scope for raising the roof without exceeding the limits of the attic as a non-full storey. I also do not see the desired flat roof extension here as compliant with the plan and with little chance for exemption. In this respect, the expansion of the house in width and continuation of the existing house profile seems to me to be the only possibility. Due to few or no building gaps in the overall "southern part," I also see no reason to consider an amendment to the development plan at least until the area of the allotment garden complex should possibly be permanently built on according to the principle of appropriateness. I therefore see that you will have to significantly reduce the scope of your modernization plans with regard to the house design. Theoretically, you would be "allowed to take revenge" on the facade, at least the development plan would not prevent that.

I would definitely swap the living area and the kitchen. As it is now, the living area is a walkthrough room – do you want that? On the other hand, the kitchen is in a cozy corner – which in my opinion doesn’t have to be the case. Since you’re doing a major renovation anyway, relocating the connections shouldn’t be a problem, but a couch that everyone walks past when they want to get a soda from the fridge, and a kitchen where I have to carry my groceries through the whole house, wouldn’t be my idea of comfortable living. And if the extension is going to stay as it is, I would also swap the bathroom and bedroom there to have the quietest corner as the sleeping area and an en suite bathroom and dressing room. Otherwise, the early riser has to go to the bathroom first, then hurry through the bedroom to the dressing room – unnecessary!

I would definitely

... first of all recommend your facade as a model to follow if it absolutely has to be something fancy and new :)