ᐅ Floor plan of a single-family house with a separate apartment on the south-facing hillside above the street

Hello everyone,

We are currently planning a single-family house on a sloped site above the street. Due to the slope, the basement level is exposed towards the street side, where a secondary apartment (granny flat) will be located. The main entrance to the house will also be at street level and then lead via a long staircase to the ground floor. I’m curious to hear what you think about this concept. Thanks!

Development Plan / Restrictions
Plot size: 627sqm (square meters)
Slope: Yes, the plot is elevated above street level. Measured from street level, about 5.5m (18 feet) at the rear left and 4.2m (14 feet) at the rear right.
Site coverage ratio: 0.4
Floor area ratio: None specified
Building envelope, building line, and boundary: See images
Edge development: According to Article 6 BayBO (Bavarian Building Code)
Parking spaces: 2 per dwelling unit
Number of floors: 3 floors
Roof type: Gable roof
Architectural style: Tiles in red or anthracite
Orientation: Main ridge direction parallel to the street ± 10°
Maximum dimensions / limits: Roof pitch 18-26° / eaves overhangs 0.4 - 1.2m (1.3 - 4 feet) in both directions

Homeowner Requirements
Style, roof shape, building type: Gable roof with 18° pitch / anthracite tiles
Basement, floors: Basement exposed to street in front and embedded into slope at rear, ground floor, upper floor with knee wall about 1.9m (6.2 feet) high
Number of occupants, ages: Single-family house for 2 adults and 2 children / secondary apartment for up to 2 people (a couple)
Room requirements on ground floor and upper floor: Secondary apartment approx. 50sqm (540 sq ft); ground floor approx. 70sqm (750 sq ft); upper floor approx. 70sqm (750 sq ft)
Office: Home office (see ground floor)
Guests sleeping per year: None (if so, on the sofa)
Open or closed architecture: See images
Conservative or modern style: See images
Open kitchen, cooking island: Open U-shaped kitchen
Number of dining seats: 8
Fireplace: Swedish stove with external stainless steel chimney
Music / stereo wall: No
Balcony, roof terrace: No balconies / terrace with southwest orientation
Garage, carport: Double garage
Utility garden, greenhouse: See images

House Design
Planner: So far, DIY
What do you particularly like? The sloped site makes the secondary apartment on the lower level convenient, while still allowing for two separate gardens on different levels.
What do you dislike?

• With this design, we place the house exactly in the southern corner of the plot to enable the secondary apartment
• We believe this is acceptable because there is a morning terrace facing east and a larger area/terrace facing the evening sun
• Because of the secondary apartment, our basement storage rooms are quite limited

Price estimate according to architect/planner: ???
Personal price limit for the house, including fixtures and fittings: max. 600,000€ (Hopefully about 50,000€ of that can be reclaimed via KfW funding)
Preferred heating technology: Ground-source heat pump (deep drilling)

Why does the design look the way it does?
We visited another house in the same development that is also on a slope above the street and has a secondary apartment below. We took some ideas from that. It was important to us to avoid having to climb around the outside of the house to reach the entrance and to have the main entrance at ground floor level. We wanted to enter the house directly at street level, covered.

What is the key/basic question about the floor plan summarized in 130 characters?
Maybe you have some good ideas for hillside construction and light wells for the secondary apartment’s windows. Otherwise, I’d appreciate your general opinion on our current plan.

Looking forward to your input and thanks in advance!