ᐅ Semi-detached house, 2.5 stories, with basement, containing 3 apartments

• Plot is 12 m wide and approximately 50 m deep
• The street-facing side of the house faces almost exactly southwest, so the garden is located to the northeast
• The street has moderate traffic (I estimate about a thousand vehicles including buses – it is the access road to the neighboring district, but there are plenty of times when one can cross the street with eyes closed)
• A 2.5-story semi-detached house, attached to the neighboring house and about 7 m (23 feet) deep, previously stood on the plot (I would guess from the 1950s). Like the neighboring house, it was later extended with a two-story addition, although the addition on "my" plot was about 1.5 m (5 feet) lower than the neighbor’s and extended further to the right.
• The neighboring building is on the left, roughly northwest
• On the “free” side of the house (south side; right from the street view) there is a residential building (~10 m (33 feet) tall) with only about 1.7 m (5.5 feet) setback from the property line, which shades the southeast gable wall of my house in winter
• The original 7-m (23 feet) house was basemented, the extensions were not
• The house was vacant for a long time and was therefore demolished by the current owner of the plot (the basement was filled with construction debris, the slab remains but is of course no longer usable)
• Distance from the facade to the street about 4.7 m (15.5 feet)
• The street rises about 1.2 m (4 feet) from left to right (when looking at the house)
• The top edge of the old house’s basement ceiling was about 1.4 m (4.5 feet) above the lowest point of the street
• There is no zoning plan / building restrictions plan, so I only have to conform to the neighboring buildings and the general building regulations (Rhineland-Palatinate)
• If I follow the footprint of the previous building on the plot, I can (and want to) build a semi-detached house with 9 m (30 feet) width and 11.5 m (38 feet) depth and extend it on the “free” house side by theoretically up to 5 m (16 feet) (3 m (10 feet) would be sufficient for me)
• I must especially follow the roof pitch of the neighboring house on the street side (about 41°), but I can also make the roof higher and make the house, as before, 1.5 m (5 feet) longer/deeper than the neighbor’s (there are similar examples in the immediate neighborhood, I have already shown the plans to the responsible building authority official and he saw no problems)
• (the thick column on the left side of the house visible in the screenshot supports cables from which a street lamp hangs above the road)

The plan is a KfW-40-qng house for rental purposes with

• about 45-50 m² (480-540 sq ft) basement apartment; the rest will be technical and storage rooms, entrance on the left side facing the street
• an accessible and senior-friendly apartment on the ground floor (about 90-95 m² [970-1,020 sq ft]), entrance also from the street side
• the ground floor has an approximately 3 x 5 m (10 x 16 feet) extension towards the garden (northeast), which is used as a balcony on the upper floor
• possibly the walls between kitchen and living room on the ground floor can be removed, which might improve accessibility
• a two-story apartment on the upper floor and attic floor with about 77 m² (830 sq ft) each, minus roof slopes; separate entrance via external staircase on the (side) gable wall
• special feature on the upper floor: the guest toilet is located under the stairs (I know of an apartment where this was under a roof slope with 1.5 m (5 feet) height — which worked fine, so this should be possible here as well, although footstep noise could potentially be an issue)
• roof pitch on the street side (left in plans): approximately 41°, on the garden side with a knee wall height of 1.2 m (4 feet) (possibly higher) about 25°
• in the floor plan, I have drawn the rather thick 473 mm (19 inches) exterior walls of my passive house; thinner walls and thus larger rooms are always easier to achieve than vice versa
• door widths are generally set to 90 cm (35 inches) (primarily for accessibility on the ground floor)
• whether the extension in the basement is basemented or only has a cantilevered slab depends on budget and the QNG calculation
• windows and furniture are only roughly sketched in

The plan is my own design (created using SketchUp; terrain modeling in the program is somewhat difficult, so please don’t complain about the staircases “floating” in the air).
I tried to use the space as efficiently as possible, although the two L-shaped rooms on the upper and attic floors bother me slightly (on the other hand, my childhood bedroom looked similar).

The building code of Rhineland-Palatinate states basically that a building with three housing units can be classified as building class 2 instead of 3 if it is on a slope (I hope the 1.2 m (4 feet) sideways and 1.4 m (4.5 feet) from the street qualify) and the lowest unit has a separate exit (one of the reasons I chose separate entrances and external stairs, besides space saving).