Single-family house city villa approx. 180 sqm + separate apartment 70 sqm - open design

We have also given some thought to the basement. We could only extend the house to the south, but then the upper floor would be too large. Enlarging only the ground floor doesn’t fit and doesn’t look good. And there is no space for a fitness room :) Additionally, there is currently a house with a basement on the property and we have to do some digging anyway.

Sorry, forgot the answer regarding the skylight. It is not planned so far,

So nothing stands in the way of a full basement "overbuild" of the granny flat with storage rooms after all. How sacrosanct and infallibly established is the knowledge that using the existing building, at least in part, makes so little sense that complete demolition down to the foundation is the royal road? Especially with a complete demolition, I would first examine the at least partial reuse of the existing structure with an open mind. A complete demolition just as a gesture of love to a dream staircase would be at least sinful luxury if the condition of the existing building was still good.

When I think of a skylight, the first terms that come to mind are "construction costs," "airtightness," "benefit," and "maintenance." I don't have any information in this regard and would gladly be enlightened :)

The granny flat does not require a basement. I believe it would be a bit far-fetched to tear down a house just because you want a straight staircase, especially since that could theoretically be done through a renovation. Unfortunately, the condition is not good; the building is quite old and has been minimally maintained. With a complete renovation + conversion (since a granny flat is needed and the space in the house is not sufficient), there are problems with the city and the building envelope. The house was there before the development plan was drawn up. Therefore, a building envelope was simply placed on the current property, but the existing building significantly exceeds the boundaries. The current basement is a crawl space basement, maybe 1.50-1.60 meters ceiling height.

I did not want to recommend skylights either, but only wanted to provoke the question of whether anyone had something more sophisticated planned for the room above the granny flat than simply building the "basement" for the main living unit above the granny flat. Please show where the house entrances are currently located. Under the given circumstances, I would only keep this part, demolish or fill/cover the further existing basement, and place the utility room and storage rooms above the granny flat.

At the entrance there is a guest cloakroom, the family cloakroom is realized as a built-in wardrobe in the hallway to the garage.

The dimensions are quite clear that many things are rather too narrow: the staircase is too short, the living area is rather uncomfortable due to narrowness and length, you will almost have the entrance door in view from the sofa and vice versa. I find these theoretical 3 meters each for kitchen/dining/sofa unsuccessful. Basement stairs would be okay. Second hallway practically from garage to house, I would close that and not just plan a small built-in cupboard as main cloakroom. The granny flat doesn’t work, there is too little space in the bedroom and entrance. Do I see a mega long driveway to the garage, which is arranged rather centrally outside the building window? I would definitely make a perimeter development out of it and rotate the garage. I would plan the house a bit wider. As it is, it is rather “insufficient”. But that’s not possible due to the building window. I would start over.

My comment about the skylight referred to Hampshire's response. The basement above the [Einliegerwohnung]? I have to admit, you’ve lost me now :) The house connection should be from the street from which you approach the main entrance of the single-family house. I can’t say exactly right now, I need to clarify with the current owners.

The staircase is too short? Honestly, the dimension of the staircase comes from the architect, 4m long and 1m running width. What would be correct here so that we can address it and make the appropriate changes. So would you suggest painting the hallway and instead planning a pure kind of wardrobe as a room? And then only using the main entrance? The idea was to go directly from the garage into the storage room -> kitchen or from the garage into the living room; that is one of our must-haves. Additionally, the path to the guest WC from the garage should be short. How much bigger should the bedroom in the granny flat be? Presumably, everything will be shifted up by 0.5m. The driveway to the garage is relatively normal; I have roughly drawn the current driveway.