Floor plan optimization of a single-family house with a basement on a small plot

The plot/the strip of land between us and the street that has a small ditch belongs to the municipality, and it should remain that way.

Then special attention is required, as the designation as a residential building area in the development plan can at least be described as thoughtless, if not even as a planning error. You should contact the municipality immediately, as encumbrances under building regulations will be necessary here. Since the wheels of public administration usually turn very slowly, you should have the willingness to assume the encumbrance confirmed in writing.

A function as a real ditch is not known, it can be filled in according to the developer.

This is very surprising, as the plot is explicitly mentioned in the justification for the development plan as belonging to the receiving water body, which plays an essential role in rainwater drainage.

It remains that the building boundary on the street side starts at 5m from the street

… which is part of the thoughtlessness of the planning.

so no 3m from the property boundary have to be observed

Since this is not a building line, I do not see the regional legal provisions regarding distance requirements as overridden here, so 3m would indeed have to be observed to the municipal property unless the willingness to assume the distance regulation is declared.

but we will not do that before the final survey

If there is no risk that someone else will buy the property, that is okay.

Our new neighbors have already done this, so in my opinion it should already have been surveyed.

No. It is not uncommon to define a precisely described partial area in the purchase contract and to divide it physically later. Only somewhat higher fees for the notary and land registry office apply.

My question would still be whether it absolutely has to be 2 full floors for a staircase to the attic or whether a high kneewall with a dormer would also be possible?

I do not understand the question. You already have a high kneewall and a dormer (correctly a cross-gable). What is the matter with the staircase?

Please ask your builder to regularly draw in the property boundaries when he sends you a floor plan. Of course, the house can be built wider than the builder has done or like in the Lichthaus, but then you will be sitting on the terrace either at the fence or on the street. Do you want that?

If I were you, I would first consider what should happen with the height difference to the street. I have to admit that I am not very familiar with basement prices: Is a white tank (waterproof basement) unaffordable? If that would be necessary, would the basement then be dropped?
Apparently, with a basement, flat windows in the "basement" rooms would be possible if you accept the stairs at the entrance. Raising the terrace—is that an option? It can all be quite smooth but the costs! Uff!

On the other hand, without a basement, the house will also have to be raised, right? What exactly does "medium height" mean now? Is it enough to adjust only the house and the paths? What would be the minimum that the ground floor floor has to reach?

I don't understand the question. You now have a high knee wall and a dormer (correctly a Zwerchhaus). What's the deal with the stairs?

I don't understand the question either. In fact, it seems even more accurate in this case to call the Zwerchhaus a bay window, since it - still unexplained! - protrudes ridiculously far from the facade, which makes no sense to me as to what purpose that should serve.

What exactly does "average height" mean now?

Since the street has hardly any slope, I estimate about 10cm / 20m, the ground floor must be at least at street level; more precisely, you have to measure and average the street height (yes, which one anyway - property boundary or street axis) at the beginning and at the end of the property. This brings us directly to the next planning uncertainty, as the development plan does not specify whether the finished floor or the structural floor is meant. Regarding the possibly necessary embankment, we probably have to make do without a height plan and accept the builders' estimates of 60cm-80cm.

Good evening everyone,

sorry for the late reply, we knew we would receive the soil report today and have studied it.

You should immediately get in touch with the municipality, as building encumbrances will be necessary here according to building regulations.

Since this is not a building line, I do not see the state regulations regarding setback distances overridden here, so that a 3m distance to the municipal property must indeed be maintained unless a willingness to assume the setback is declared.

These are two very good remarks, thank you for the advice. Unfortunately, we are laymen in this area and assumed that if it is stated like this in the development plan and approved, then it can be done that way. We will inform ourselves further and try to address these two issues.

No. It is not uncommon to define a precisely described partial area in the purchase contract and then divide it physically later. Only somewhat higher fees for the notary and land registry office apply.

Okay, it just seemed unusual to us because this has already happened with the other southern plots.

I don’t understand the question. You now have a high knee wall and a dormer (correctly a gable dormer). What about the stairway?

My thought behind it was that you don’t build two full floors completely, but rather a very high knee wall and the stairway from the ground floor to the first floor continues further to the attic, to have one or two rooms there. Similar to the Lichthaus 152 from Town & Country, without the stairway needing to be in one of the rooms on the gable side in the attic.

The soil report summarized the following results:

[*]Difference to the street edge max. approx. 1m in the northeast, slope also to the northeast (As I understood the text, they also consider the street axis and not the property boundary, unlike the soil report)
[*]Upper area must be excavated at least 1.5m and refilled. Ultimately, the load-bearing layers – with a bit of compaction – begin between 2m and 2.30m
[*]Excavated soil is suitable for modeling the property. It would ultimately have to be done so that the top 30-50cm of good soil is set aside, the soil below is used for modeling, and then the good soil is put back on top.
[*]A white tank foundation was recommended (stiff to semi-firm claystone from 2m to 2.30m, poor infiltration). In times of increased precipitation, pressurized water should be expected, but not in good weather.

I would first consider what should happen with the height difference to the street at your place.

As far as I understood, it has to be filled in. With a basement, the excavation volume should roughly match quite well.

Is a white tank unaffordable? If that would be necessary, would the basement then be off the table?

According to the BU, a white tank costs about 20k more than a black one. No, it wouldn’t be unaffordable. Overall, the basement with a white tank would be an extra 70k compared to one and a half floors without a basement and the same footprint, etc. The big question (what a great pun ) is, what difference does the basement still make compared to two full floors if you have to significantly excavate the subsoil anyway, that’s not enough to align with the street axis, so you still have to fill in and also have to use extra material for the slab because you’re not digging as deep as with a basement. That’s what we ask the BU.

Propping up the terrace – is that an option? That could all be quite smooth but the costs! Uff!

I don’t see that as problematic. We would do the terrace ourselves, with support from family (I think we have a few capable people there), and then something like decking with an understructure supported on point foundations. In front of the larger height differences to the stairs/embankment, planting, done. That should stay within budget.