Floor plan improvement suggestions for a single-family house on a south-facing slope

A basement under the garage can make sense, as far as we know so far, especially on a slope due to the soil conditions.

Whether a garage basement is reasonable, I don’t want to judge here. The slope itself is rather facing south, in the middle of the property.

The plan for the basement is not yet ready.

But it should be! It is a major cost factor.
Your three desired floors including living basement including possibly a granny flat I do not see within the budget. I have the feeling that you are designing the dream house on your own and do not consider that one floor costs about €200,000. Already this roof terrace on the basement is a cost and weakness factor in house construction.

Your plot naturally allows for a basement almost by default. Nevertheless, you don’t have to use the entire height. That all costs real money. In addition, your rooms are partly quite narrow, the living room as well as the upstairs children’s rooms are at the pain threshold for being corridor-like. In this respect, you would have to increase the floor area somewhat.
I would first try to allocate comfortable living space for the mandatory rooms, then see if there is anything left financially.

Price estimate according to architect/planner: not yet obtained

Yes, that’s already a no-go, doomed to fail if you don’t know how much a square meter costs.

Number of parking spaces: two per residential unit in front of garages at least 5 meters

Where are your tenants supposed to park? Should they block you in the garage? They need separate parking spaces without having another car blocked. Captive parking spaces are officially not acceptable.

Number of dining seats: 8 preferably expandable

70 cm width for a chair and a place…

What makes it particularly good or bad in your eyes?

A granny flat planning does not arise. That has to be included right away, just like the use of the basement.
Personally, I would not give a tenant in a granny flat access to my garden and want to enjoy my leisure time myself on a gated deck.
Therefore, I would plan the floor area somewhat larger, the floor area ratio allows it, a residential basement and the bedrooms on the upper floor. No granny flat, I don’t see that.

The stairs to the bedrooms start from a not very attractive, uncomfortable stub of corridor opposite the garage door. There the door opens in the wrong direction; the other way around it would compete with the stair landing.
The staircase seems too short to me. Perhaps the ceiling thickness was not taken into account or something.

The cross-section of the open space is a joke. Far too narrow. What is the seat depth of the sofa???? I would draw that twice as big. But even from the dining table you would see that it is too tight. A fireplace would have no place.
The width of the children’s rooms was bigger in a 70s terraced house than seen here.
The bathroom is also quite modest in size and would be 2–4 sqm too small for me in a self-built home for 4 people.
Overall, the comfort probably lies rather in the unplanned basement and not in the living area: everything quite cramped compared to the intended living area.

Do you have tips on how to implement things similarly but cheaper?

Here’s the good: Kids have nice light orientation, utility room on the upper floor is also fundamentally a good idea. The rest is no magic and rather poorly implemented.

First of all, many thanks to all of you for your interest and numerous responses. We are trying to address some points in more detail to explain our thoughts on the planning so far.

[...]The position of the staircase is unfortunate, which leads to all rooms on the upper floor simply being impractically shaped.[...] Moving the furniture is almost impossible in these spaces. A rectangular floor plan is actually the most efficient to plan with a half-turned staircase that is placed as centrally as possible on one of the long sides of the house. It's unspectacular but efficient.

We find a staircase with distorted steps extremely uncomfortable and have therefore consciously chosen a staircase with straight steps. Both of our parents have difficulties climbing stairs. In terms of space consumption, we see some advantages with the L-shaped staircase compared to, for example, a straight staircase (very long, requires a lot of hallway space) or a U-shaped staircase (1 m² less). Furthermore, due to the shape, the entrance area is not as cramped as in some houses where the spiral staircase starts directly next to the door.

Often, in houses with a straight staircase, the living area is visually separated from the dining area, but we do not like that, as you can hear everything from the kitchen and dining area there, but cannot participate in the communication. We prefer a combined cooking, living, and dining area.

Basically, we have tried to plan as barrier-free as possible given the space conditions --> most doors have a clear passage width of at least 90 cm. In addition to the doors, we also consider the staircase to be one of the biggest barriers in the house and therefore it should, if possible, have a straight running surface.

The house lacks depth. Children's rooms and living room are too narrow.

If you mean that the children's rooms are too hallway-like, what room proportions would you recommend? What minimum depth?

Just this roof terrace on the alone is a cost and weakness factor in house construction.

Of course, that is a point we have also recognized; as an alternative, we had planned to design the basement outer dimensions to match the ground floor outer dimensions and construct a terrace as a steel structure. But I believe the costs here also strongly depend on the construction, regardless of whether it's an extended basement or steel construction.

Where are your tenants allowed to park? Are they supposed to park blocking you in the ? They need separate parking spaces without another car blocking them in. Trapped parking spaces are officially not allowed.

There is still an access option and parking possibility in the garden. If the granny flat is not rented out, that would be intended as a parking space for a trailer.

70 cm width for a chair and a seat…

Thanks for the suggestion. We will check that again. The planning software suggests a total length of 2.4 m for 8 seats (see picture). What table dimensions would be expected if 8 people should sit comfortably? The table width is relatively generous at 1.2 m, so there should be enough space behind to walk through; if not, the sideboard can be omitted.

Therefore, I would plan the floor area slightly larger since the floor area ratio allows it, plan a residential basement and bedrooms on the upper floor. No granny flat, I don’t see it.

That would of course be a reasonable option that would be associated with lower costs, but this possibility is to be seen as a last option due to the desired workshop area, as it would not fit there. We would of course submit preliminary plans for the basement floor in due time, then the required space might be better recognized. (Currently, another house occupies about 80 m² there.)

The staircase seems too short to me.

This is the thought we had: (15 steps 18.1 cm x 26 cm) + (18.5 cm to the top edge of the floor covering) => 290 cm story height. We will look at that again. 300 cm story height might be better, but the remaining room height strongly depends on the floor and ceiling construction.

The has a seat depth of????

That was a standard sofa from the software -> seat depth 55 cm. My mistake, I didn’t check that carefully. I have adjusted it to an overall depth of 100 cm, which corresponds to our current sofa.

Here’s the good: Kids have a nice light orientation, utility room on the upper floor is basically also appropriate. The rest is no magic and rather poorly implemented.

Nice to hear something positive for a change.

This is a typical design where the living space is planned around the staircase.

In fact, we have already significantly limited the planning with the staircase and also noticed during planning that it is not so easy with a straight staircase. If I may summarize the responses so far, the clear opinion has been to completely discard the design and strive for a new plan. Perhaps someone would like to give us a thought-provoking idea with one of the mentioned staircase types without distorted steps by suggesting a more sensible positioning in a house of comparable floor area.

I am first trying to position on the property. The terrain slope is 12.5%.

With a house width of 9m, that is 1.125 m. Is the basement already worthwhile there?

I don't see a real basement solution there. Only with considerable effort for earthworks and retaining walls.

Is there a reference point for the height of the ground floor?

Are terrain modifications allowed?

Dimensions of the property?

Exactly, the terrain slope is about 12.5% (which only applies to the street). Viewed diagonally, it is somewhat steeper. Taking into account the length of the garage (a total of 16m), there is already a height difference of 205 cm. The height of the ground floor should be roughly at the level of the highest point of the property (3.9 m above the lowest point of the property). A basement under the cellar would already lead to less earthworks being required on the eastern side of the property. I have attached a screenshot of an east view including the overlaid original terrain.

Regarding earthworks, the following two points from the development plan apply:

Garages that lie below the level of access roads may, after filling of the original terrain (max. 2.00 m) up to the level of the access road, still have an additional wall height of max. 3.00 m; the average wall height is set at 5.50 m.

The FFOK ground floors of the buildings are to be placed at the level of the respective access road (reference point = highest point in the driveway area). A height difference of up to max. 0.5 m is permitted for parcels that lie below the access road and up to 1.0 m for parcels or the multi-storey residential buildings and the mixed-use area that lie above the access road.

The dimensions of the property are width 24.95 m (along the street) and depth 27.2 m. The property is to be considered rectangular.

Are the 650k purely for the house (could be possible) or for the project including earthworks, slope retention, etc.?

In the latter case: plan new, plan smaller.

Please respond to that.

Because what you are planning is technically all feasible, but given the size of the project, you need a very deep pocket.

For the budget, you are planning one floor too many
The basement is removed,
the ground floor moves to the basement with direct access to the garden
the problem of the terrace on the basement is gone
the attic moves to the ground floor