Floor plan optimization single-family house 140m2 on narrow plot

Hello everyone,

we have the opportunity to purchase a plot of land including a house. However, the existing house is in a condition that requires demolition. Our plan is to build a new, small single-family house with about 140 m² of living space. Since we would like to build with a basement and the existing house had a basement, we are somewhat limited in the positioning of the new house.

We have already received a first draft from a prefabricated house manufacturer. I have drawn this floor plan into the site plan and made a rough planning of the outdoor facilities. Now I would like to get your expert opinions on this draft. In the near future, I also plan to contact a local construction company or architect to obtain another offer – perhaps already with a more concrete idea of the floor plan.

Development plan/restrictions
Size of the plot: 710m²
Slope: no
Site coverage ratio: -
Floor area ratio: 2
Building window, building line, and boundary: drawn building line does not exist according to the municipal building regulations department
Edge development: -
Number of parking spaces: -
Number of floors: -
Roof type: -
Architectural style: -
Orientation: -
Maximum heights/limits: -
Other specifications: -

Requirements of the builders
Architectural style, roof type, building type: gable roof or hipped roof
Basement, floors: with basement + 1.5 or 2
Number of persons, age: 2 adults (30/31 years) 1 child (1 year), another child planned
Space requirements on ground and upper floors: ground floor preferably with office and pantry, upper floor bedroom with small dressing room, two children’s rooms and one bathroom
Office: family use or home office: home office, but if possible should also have space for a sofa bed (guest room)
Guests staying overnight per year: 2-3
Open or closed architecture: -
Conservative or modern construction: modern construction
Open kitchen, kitchen island: open kitchen
Number of dining seats: min. 4, but expandable to about 12 people for special occasions
Fireplace: not required
Music/stereo wall: no
Balcony, roof terrace: no
Garage, carport: garage if the budget allows
Utility garden, greenhouse
Other wishes/special features/daily routine, also reasons why something should or should not be: house should be planned with a basement, as basement excavation is already available after demolition.

House draft
Who designed the plan: prefabricated house manufacturer
-builder of a construction company
-architect
-do-it-yourself

What do you particularly like? Why?
The floor plan largely meets our wishes on the ground floor: an entrance on the north side, an office overlooking the driveway, a kitchen with an adjacent pantry, and an open living and dining area. On the upper floor, there is the option to set up a second home office place in case we both want to work from home at the same time.

What do you not like? Why?
The straight staircase, which is visually appealing, unfortunately takes up a lot of space on the upper floor, making the children’s rooms quite small. Also, the office on the ground floor offers no space for a sofa bed. The arrangement of the doors in the entrance area as well as the stair ascent from the living and dining area to the upper floor are not ideal with children.

Price estimate according to architect/planner: 300,000 € from top of foundation slab (excluding flooring, painting, interior doors, etc.)
Personal price limit for the house, incl. equipment:
Preferred heating technology: air-to-water heat pump

If you have to give up anything, which details/extras
-can you do without: pantry/ straight staircase
-can you not do without: office, basement

Why is the draft the way it is now? For example
Standard draft from the planner? Standard floor plan from prefabricated house manufacturer
Which wishes were implemented by the architect?
A mix of many examples from various magazines...
What makes it particularly good or bad in your eyes?

Many thanks for your opinions and support.
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Personal price limit for the house, including equipment:

?

Price estimate according to architect/planner: €300k from top of foundation slab (excl. flooring, painting, interior doors, etc.)

Is this a shell house that is being built on an existing basement?

?

Is this a shell house being built on an existing basement?

Personal limit is: approx. €350,000 (excluding basement, garage, photovoltaic system, sanitary fixtures, floor coverings, interior doors, painting, kitchen, incidental construction costs, and outdoor facilities)

No, the basement must be demolished as well.

The personal limit is about €350,000 (excluding basement, garage, photovoltaic system, sanitary fixtures, floor coverings, interior doors, painting work, kitchen, incidental construction costs, and outdoor facilities)

And what is the budget for the listed items?

No, the basement must also be demolished.

Why? I would also be interested in the problem with the existing house that makes it "irreparable." Is there dry rot? Woodworm in the roof? Cracked walls?

And what is the budget for the listed items? Why? I would also be interested in the problem of the existing house that makes it "irreparable." Is there dry rot? Woodworm in the roof? Cracked walls?

I have planned the following for the listed items: - Basement: €100k - Garage: €40k (optional) - Photovoltaic system including storage: €21k - Sanitary fixtures: €15k installation by myself - Flooring: €7k (no tiles) installation by myself - Interior doors: €5k installation by myself - Painting work: €10k with my own effort and a relative who also does seamless bathrooms, therefore no tiles - Kitchen: €20k - Additional construction costs: approx. €50k (excluding demolition) - Outdoor area: €20k Here are a few key facts about the existing property: - no renovations have been carried out - House was not well maintained -> lots of mold on the walls - Basement height very low - Electrical wiring still two-core - The house only has 99 m² and the layout is so unfavorable that almost every interior wall would have to be moved to achieve a somewhat reasonable floor plan. - Due to the small size, we would have to do an extension - Roof would have to be redone - New windows - Facade insulation - Heating system new etc. If we completely renovate the house, I doubt we would come out cheaper, especially with an extension. In the end, we would have a house with many compromises that still dates from 1955. I also consulted independently with two acquaintances (one was an architect, the other a bricklayer), and both believe it makes little sense to hold on to the existing building. The selling price is accordingly such that we would basically only be paying for the land.

Thank you very much for the list. That makes it a bit easier to understand. Regarding the floor plan: I would first think about the orientation. The garden is the second living room in summer. Therefore, I would orient the main rooms towards it (And not towards the neighbor!). The living room in the northeast, kitchen and dining room in the southeast. The straight staircase is not ideal in my opinion. With a basement, a U-shape is usually better in smaller houses. I still haven't understood why you absolutely want to see the street from the office. Are visitors or clients coming there?