Single-family house with a separate apartment currently for 2 adults, children planned

Thank you very much for the feedback so far!!

I worked with Sweet Home 3D, and there were only these stairs. But good point that they are too small.

I work in elderly care/disability support. And a stairlift is not always a functional solution. That’s why I at least want to have the option to place the bedroom on the ground floor. Until then, the room can also be used differently (office, part of the living room, whatever).

I’ll look for the drainage thread right away.

True, the designation utility room was inappropriate. It was rather meant as a pantry and to be able to store the vacuum cleaner/ironing board.

We actually have no "mega complicated" or "extraordinary" requirements.

The high basement is due to the high groundwater, which pushes up during floods, otherwise a plinth would have to be built and the space would be "wasted."

And in various threads you often read that a basement is cheaper than building the same area above ground.

The idea with the separate dressing room is good, thank you!

The granny flat is actually not strictly necessary. It was an idea for financing (both regarding subsidies and rental income), but we are also unsure if we really want it.

The appointment with the architect was unfortunately postponed at first due to Corona and that’s why I started to plan roughly. Maybe I better wait for the professionals

Thanks for your advice!!

And a stairlift is not always a functional solution.

I am not a professional in this area, but I ask myself: if I am so old/frail/whatever that I can’t even use a stairlift, can I even still live in the house, or does that still make sense?

Idea for financing

It only pays off in very few constellations. And first of all, you pay a lump sum on it, which you slowly have to get back through (taxable) rental income.

I see a design of about 14 meters wide and 8 meters long.
(This makes about 110sqm living space per floor)
If we add some strong and insulated exterior walls to the design, we are at 14.8 x 8.8 external dimensions.

14.8 house width + 3 meter garage on the left + 6 meter carport on the right = 23.8 meters
But the plot is only about 21.60 ...

That’s why I at least want to have the option to put the bedroom on the ground floor. Until then, the room can also be used differently (office, part of the living room, whatever).

Such a wish must also be affordable.
You have other wishes as well, which I will address, so a bedroom on the ground floor should be the least problem if you disregard the space requirement.

Basement + 2 floors:
100000 basement (110sqm)
440000 house (220sqm)
10000 fireplace including chimney
5000 sauna
12000 garage
10000 double carport
20000 interior finish

Preferred heating technology: geothermal heat pump or pellet heating with Stirling engine, possibly photovoltaics and/or solar thermal (consultation appointment still pending)

also an expensive undertaking.

If I replace the costs of carport and garage with those of the desired photovoltaic heating, we are at about €600,000 plus outdoor facilities of about €50,000.
With €300,000 it will be a 130sqm house without basement and frills.

I work in elderly care/disability support.

That’s why the designation "Pilot" as well.

Sorrrrrryyyyyyy, that’s not going to happen.

1. If you already need an elevator, you are quite limited. If it no longer helps, a house will be of no use.

2. A basement is not necessarily cheaper than above ground, especially since you then also need a WU basement.

3. A condominium is not worthwhile.

4. Your budget is nowhere near enough.

I did not understand "Keller / Hochkeller" in the slightest - both floors look above ground on all sides, and even the site plan (of course: without contour lines) gives no indication of what that might mean. I would only consider a secondary apartment if the tax advisor conclusively proves the special case that it pays off - as a rule, this is likely a mixture of zero-sum game and Hornberger shooting. At the ages of 32/37, age-related pre-planning is not sensible, since one rather belongs to the generation "building again close to retirement." I actually find working with floor plan sketches with symbolic partition walls good for laypeople in structural engineering - as long as one does not forget to add appropriate allowances for the real wall thicknesses. Otherwise, it is advisable to simply calculate all interior walls at 20 cm and all exterior walls at 40 cm. Individual floor plan planning without any special requests is mere play.

I'm just going to look for the drainage thread now.

It was last mentioned in this topic (quite far back):

It was more intended as a pantry and to be able to store the vacuum cleaner/ironing board.

That wouldn't work like that, then you wouldn't be able to open the door/get into the room.

And in various threads you keep reading that a basement is cheaper than building the same area above ground.

Maybe the same area, but how much space do you REALLY still need?
If you leave out the granny flat with the same external dimensions, you would have already gained so much space! And voilà, €100,000 "saved" (cf. ypg’s calculation)

The granny flat is actually not strictly necessary. It was an idea for financing (both regarding subsidies and rental income), but we are also wavering on whether we really want it.

Hopefully you are wavering towards: No, we don’t need it.
What do you have from your own house if it’s not your own=sole house.

Maybe I’d better wait for the pros

That would be sensible. Although:

Floor plan customization without special requests is nonsense.

I can only agree again!
Take a finished general contractor floor plan (I don’t know all the providers now... Gussek Haus, Bien-Zenker, Town & Country and god knows what).