ᐅ Single-family house converted for two families: experiences with floor-by-floor separation?
Created on: 8 Apr 2026 07:45
M
mmyellow
Hello everyone,
We are currently at the beginning of a construction project in Ludwigsburg (Sonnenberg South-West development area) and would like to gather early feedback on the choice of plot and the overall concept.
The plots are allocated through an application process (up to 3 preferences possible, selection not guaranteed). We currently have 4 possible plots shortlisted and need to prioritize them.
Development Plan / Restrictions
Plot size: approx. 440 – 525 m² (4730 – 5650 sq ft)
Slope: no (relatively flat)
Site coverage ratio: 0.4
Number of floors: 2 full stories
Building type: detached construction, single-family or semi-detached houses allowed
Roof style: flat roof (max. 3° pitch, specified)
Maximum height: approx. 9 m (30 ft) to parapet
Special conditions:
• Green roof required
• Photovoltaic system planned / can be integrated effectively
• No underground garage allowed
Homeowners’ Requirements
The plan is not for a conventional single-family house but:
A single-family house to be used by two families, separated by floors
(confirmed provisionally by phone and building regulations, final feedback pending)
Concept:
• Ground floor: approx. 140–160 m² (1500–1700 sq ft) + garden
• Upper floor: approx. 150–160 m² (1600–1700 sq ft)
• Goal: long-term use, not an investment
• rather modern, clear architecture (flat roof is mandatory anyway)
Households:
• two families (each early 40s, each with one child)
Additional requirements:
• preferably quiet location within the development area (no through traffic)
• good orientation (garden ideally facing south)
• practical access / parking solution (2 garages + 2 carports planned)
House Design / Current Status
Who is designing it:
Currently do-it-yourself / concept phase
What is still open:
• Construction method (prefabricated vs. solid, wood vs. concrete)
• Floor plans
• Basement (partial vs. full)
Our Questions to You
Which plots would you generally prefer in such a development area (quietness, location, orientation)?
From your experience, are there any “typical mistakes” in plot selection that only become apparent later?
How critical do you consider the concept of “two families in one single-family house separated by floors” from a practical point of view (sound insulation, everyday life, usage)?
What would you pay special attention to regarding the placement of garage/carport and access?
We are aware that we are still early in the planning and open to honest feedback.
The concept is still under discussion, especially regarding a suitable second family. If anyone is in a similar situation or wants more information, just search for “Sonnenberg South-West”; we are happy to exchange ideas.
Thank you very much!
Best regards
Richard
We are currently at the beginning of a construction project in Ludwigsburg (Sonnenberg South-West development area) and would like to gather early feedback on the choice of plot and the overall concept.
The plots are allocated through an application process (up to 3 preferences possible, selection not guaranteed). We currently have 4 possible plots shortlisted and need to prioritize them.
Development Plan / Restrictions
Plot size: approx. 440 – 525 m² (4730 – 5650 sq ft)
Slope: no (relatively flat)
Site coverage ratio: 0.4
Number of floors: 2 full stories
Building type: detached construction, single-family or semi-detached houses allowed
Roof style: flat roof (max. 3° pitch, specified)
Maximum height: approx. 9 m (30 ft) to parapet
Special conditions:
• Green roof required
• Photovoltaic system planned / can be integrated effectively
• No underground garage allowed
Homeowners’ Requirements
The plan is not for a conventional single-family house but:
A single-family house to be used by two families, separated by floors
(confirmed provisionally by phone and building regulations, final feedback pending)
Concept:
• Ground floor: approx. 140–160 m² (1500–1700 sq ft) + garden
• Upper floor: approx. 150–160 m² (1600–1700 sq ft)
• Goal: long-term use, not an investment
• rather modern, clear architecture (flat roof is mandatory anyway)
Households:
• two families (each early 40s, each with one child)
Additional requirements:
• preferably quiet location within the development area (no through traffic)
• good orientation (garden ideally facing south)
• practical access / parking solution (2 garages + 2 carports planned)
House Design / Current Status
Who is designing it:
Currently do-it-yourself / concept phase
What is still open:
• Construction method (prefabricated vs. solid, wood vs. concrete)
• Floor plans
• Basement (partial vs. full)
Our Questions to You
Which plots would you generally prefer in such a development area (quietness, location, orientation)?
From your experience, are there any “typical mistakes” in plot selection that only become apparent later?
How critical do you consider the concept of “two families in one single-family house separated by floors” from a practical point of view (sound insulation, everyday life, usage)?
What would you pay special attention to regarding the placement of garage/carport and access?
We are aware that we are still early in the planning and open to honest feedback.
The concept is still under discussion, especially regarding a suitable second family. If anyone is in a similar situation or wants more information, just search for “Sonnenberg South-West”; we are happy to exchange ideas.
Thank you very much!
Best regards
Richard
The idea was more that you bring your suggestions without any preconceptions. But no problem, here are 3 ideas, 2 of them with a garage parallel to the street.
The others I have only worked out in 2D without dimensions so far, but I will provide those as soon as possible.
The others I have only worked out in 2D without dimensions so far, but I will provide those as soon as possible.
H
hanghaus202313 May 2026 14:45My suggestion is based on dividing the plot. Otherwise, it won’t work. Now you are looking for a partner for a semi-detached house.
hanghaus2023 schrieb:
Is there a development plan? YES
mmyellow schrieb:
https://www.ludwigsburg.de/site/Ludwigsburg-Internet-2020/get/params_E-1592578321/25070941/Exposee%20Sonnenberg%20SW_Anlage_2_Textteil_Festsetzungen%20B-Plan.pdf Point 6:
Parking spaces, covered parking spaces (carports), or garages are permitted not only within the designated building areas, but also within the front garden areas facing traffic areas and the side setback zones up to the height of the rear building boundary (i.e., the boundary facing away from the access road). Garages must be set back at least 1.0 m (3.3 ft) from the boundary to public areas (traffic zones, sidewalks, pedestrian paths, green areas). Point 4
Secondary building elements such as balconies, bay windows, or projections up to 5 m (16 ft) in length and 1.50 m (5 ft) in depth may extend beyond the established building setback line, provided their total length does not exceed 50% of the building length. The applicable setback regulations according to the state building code remain unaffected by this rule. Your suggestion to place the carports instead of garages directly next to the house would almost work. Thanks for thinking about it.
However, I believe these count towards the floor area ratio of 0.4, so:
15 m x 11 m (main building) + 3 m x 5.5 m (CP1) + 3 m x 5.5 m (CP2) + 3 m x 2 m (setback area 1) + 3 m x 2 m (setback area 2) = 210 m² (2260 sq ft)
525 m² (5651 sq ft) * 0.4 = 210 m² (2260 sq ft)
That means you already reach the limit without paths and without the garden slab.
But the idea is good, because in addition to the 2 official parking spaces you would get 2 more spaces in front of the carport,
and the building footprint at 165 m² (1776 sq ft) comes close to the maximum of 195 m² (2098 sq ft).