ᐅ Narrow House Extension with Access to the Attic: Installing an Elevator Retrofit

Hello,

My wife and I are currently looking for a way to expand our existing house (3 condominiums) to create more living space for ourselves and the future.

Background: The house with double garage (see attachment) has 3 condominiums (ceiling height 2.75m (9 feet)). We own the ground floor (in-laws) and the top floor with flat roof. The top floor apartment, about 100m² (1,076 sq ft), would then be for us.

Idea: Since an extension on top of the house was not approved by the building authority, the architect suggested the first option: to build an extension above the double garage, which is about 5m (16 feet) wide (red drawing). The footprint of the extension would be 9x5m (30x16 feet). Since the house is about 11m (36 feet) high, the plan was to have an integrated garage on the ground floor, living space on the first floor, and additional living space on the top floor with a connection to the existing apartment and enlargement of the balcony. The existing stairwell to the top floor apartment would be separated. This way, the extension would become a separate house, but still connected to the existing one (like an L shape rotated 90°). The double garages would be rebuilt for the other owners on the other side of the property.

Challenges: The house stands on a plinth (1.5m (5 feet)). Therefore, from the integrated garage to the first floor, a stair height of almost 4m (13 feet) must be overcome.

We have started to roughly define the layout for ourselves. Aside from all the theory, the problem of stairs and later the possibility to retrofit an elevator might be a concern.

Ground floor: integrated garage
1st floor: kitchen + pantry, dining room (shopping would not have to be carried far)
Top floor: usual living and sleeping area with 2 bathrooms.

Conclusion: We find the idea very interesting since living space in Frankfurt (Rhine-Main area) is very expensive. I would appreciate if you could share your ideas, especially regarding the staircase issue. I hope this is understandable to some extent.

Many things are possible, but not all are sensible. What is your assessment? I would be grateful for both positive and negative feedback.

Attachment: (Black: current; Red: renovation)

Regards
Obsthaendler

Addendum: The small red rectangle to the left of the balcony (X) represents the rooftop terrace extension in the attic. My sketch of this is a bit confusing.

Have you already inquired with the building authority / planning office? The garage is located on the property boundary. Now you want to convert it into living space, which is usually denied in our municipality. That would mean that all your plans are off.

The idea actually came from the building authority after the roof extension was rejected. Yes, the garage is built right on the property boundary.

Do you want to access the upper floor from the garage? If not, there would be the option to build an external staircase over the garage roof (the small red box in front of the house would then be a bit smaller). This way, you would have a small landing on the garage roof in front of your upper floor.

Well, the idea of having direct access from the garage into the apartment/house is nice and, above all, practical. I created another 3D view and edited it a bit with Paint. The situation is really difficult to explain.

The red area represents the 9x5m (30x16 ft) extension. The green area is the apartment/house. The floors are marked in yellow. Behind the house is the garden and the south side.

Here is another view from the south side, showing how I could imagine it with the roof terrace. On the right, you can see the extension again.