Feasibility study for extension C7, Mannheim

Our C7 project in Mannheim was completed in 2017. In early summer of this year, one of the residents asked us whether it would be possible to add an extra storey to the existing flat roof. How is it that after less than 4 years, the residents feel that their flat is inadequate and need more space?
The answer is quite simple: in many German households, working from home has significantly increased the amount of space required within the home. We spend much more time within our own four walls than ever before and the "desk in the corner", which previously only had to suffice for tax returns or the like, is now our faithful companion. Hence the enquiry as to whether it would be possible to create living space by adding a storey, which has been eagerly desired for the last 1 1/2 years.
We were very happy to carry out a kind of feasibility study in the office and compare different options. The existing flat is to be converted into a maisonette, adding an office, an additional teenage bedroom and a bathroom on the top floor.
This must be weighed up: Size, utilisation, shading, sensibility, spacing, statics

Location C7, Mannheim
Building owner private
Construction method Timber construction
Miscellaneous Year of the feasibility study 2021