Was changed in the first post due to forbidden link
A link being edited out can happen. But was there also an explanation as to why the change to a multi-story building occurred?
Since this note regarding the manufacturer or model is no longer included, this can no longer be traced.
Gussek Haus Lindenallee is not that hard to google. Does the OP want to take it over like that? — surely there is a show home for that (and also pictures of it, including inside), so you can check how it was solved there. I don’t quite believe that Gussek Haus would let feces slump down, boxed in drywall, next to the dining table in a show home (?) — that would make me lose faith, since I always recommend to builders to choose standardized floor plans under the motto "you know this has been well worked out."