House planning with 3 children's rooms on a 473 sqm plot

How are you otherwise getting along with the rest? The dirt area in front of the stairs and the lack of space for a wardrobe in the bedroom are often criticized.

The building authority said 2 full floors, preferably with a basement, and you'll have enough space

As if the building authority knows your needs. Well, if a basement fits in the budget… but what I mean: The wall height is max 5.5. So if you convey something with the maximum ridge height (which depends on the house width), then you end up with a knee wall of 2 meters (you’re not going to tell me that’s rubbish?!), with a very good attic, which can still be nicely converted into living space. I don’t have time now to sketch it.

The entrance area is definitely an issue. Ideally, there would be a vestibule or a corresponding hallway with options for a built-in wardrobe. At the moment, we have 3 Pax wardrobes and dressers in the bedroom due to the slant. It works, but it’s not exactly nice.

The building authority is only aware that we have a relatively new house, but one room is missing. That’s why contact regarding building plots was established. During the conversation, they asked why we want to get rid of our "new" house.

We are really torn regarding basements. At the moment, we have one with underfloor heating, but if we are honest, 80-90% of the stuff could go....

A usable attic as an office / storage room would of course be nice. A 2m knee wall sounds good.

Our budget is around €700k, preferably less. The building plot will be around €100k, so €600k remain for the rest.

Forget it. The 11ant is already thinking only in slope mode again. However, the level ground is photographed quite unfavorably

I am in no slope mode. You would have to know the exact heights, then you can apply the rule accordingly (I had already mentioned the search phrase, which leads to part 1 of the four-part series). I can well imagine that this would result in a utility cellar here, possibly even a partial utility cellar (in a way, a substitute attic room). But all that is discoverable (daily routine, no witchcraft). In my opinion, the picture clearly says: slope, but slight. The photographer should actually see that faster than the merchant.

that it would come down to a utility basement here

Yes, of course, what else, if it is almost flat?!

then you can apply the rule to it

There is no rule for that.
There are inclinations that call for a residential basement… no rules…
but here (if almost level is assumed) you only need common sense or, if there is a slope, then accordingly the VG point in the state building code.

Yes, of course, what else, if it is almost flat?!

It is only flat in the sense of not wildly undulating, but not also in the sense of a horizontal plateau.

There are slopes that call for a basement… no rules… but here (if almost level is taken as given) you only need common sense or, if slope, then accordingly the VG point in the state building code.

Here we are dealing with a slight slope that certainly does not call for a basement. And definitely there is no risk of a full-story basement. Whether a partial-use basement, leveling out, or piling up would be the best choice here can be examined.

There are no rules.

The 11ant basement rule is also not a rule in the sense of a regulation, but in the sense of a farmers’ saying (although astonishingly precise for such). It formulates the calculability of basement or no-basement costs taking into account the phenomenon that basement construction costs and basement avoidance costs practically convert 1:1 against each other, and describes the weight of the vote with which the terrain sits at the decision table. The naive layperson often mistakenly believes basement costs to be an easily captured fat item, and in the extreme case buries the same money (i.e. when the terrain votes two meters = one hundred percent pro-basement) for an "avoided" basement, for which they could also have gotten one built. This expensive error is made predictable by the (first) 11ant basement rule, no more and no less. A phenomenon has no fathers, not even me. I merely formulated the rule after having empirically observed it for over four decades. All just boiled down to water (which applies to both the first and the second 11ant basement rule).

The roof shape we are mentally already considering is the gable roof, the idea was 2 VG and possibly an attic for storage as a cellar replacement. Here, as mentioned, I have no idea how high the attic can be then.

Mentally with the gable roof with 2 VG I personally find good. I have myself already lived in a semi-detached house with four bedrooms, which was significantly smaller than 160sqm of living space. Just because an attic under a gable roof is perhaps not an official living area, you can wonderfully create a bedroom/office and storage space there. However, I better leave the concrete planning to others.