ᐅ Floor Plan Design for a Single-Family Home of Approximately 250 sqm with a Separate Granny Flat

Created on: 26 Jan 2025 21:52
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CornforthWhite
I already feel a bit anxious writing this, anticipating the inevitable criticism of our design, but I’m posting it anyway. We struggled somewhat with the software, so much of the presentation is still quite provisional. Our main goal is to find out whether what we’ve basically planned could work. We’re primarily looking for feedback on functional planning errors. Style critique is sure to come since our design is unlikely to suit most people’s taste here—but that interests us less (we like what we like, and that probably won’t change). Although tastes vary, I’ve learned a lot from other threads recently and hope that “the usual suspects” might also take a look at our design. Thanks in advance!

Development Plan / Restrictions

Plot size: 960 m² (10,333 sq ft)

Slope: no

Floor area ratio: 0.2, maximum buildable footprint however <175 m² (1,883 sq ft)

BUT: the 1977 Building Use Ordinance applies

  • § 19 IV: Ancillary structures according to § 14 are not counted towards the allowable footprint. The same applies to balconies, loggias, terraces, and structural elements as far as they are permitted within setback areas or distance zones under regional law (here: Bavaria) (…).
  • § 21a III: Covered parking spaces and garages are not to be counted towards the allowable footprint as long as they are less than 0.1 of the plot area.

Floor space index: -

Building envelope, building line and boundary: 5 m (16 ft) from the road on the south and west, 3 m (10 ft) from neighbors on the north and east

Edge development: no

Number of parking spaces: 1.5 per dwelling unit

Number of storeys: 1 + attic

Roof style: no fixed style, but roof pitch regulation with 2 options

Option 1: 22–26 degrees

Option 2: 33–44 degrees

Architectural style: no specification

Orientation: flexible

Maximum heights / limits: in red the official restrictions of the development plan, in green the generously granted exceptions we are aware of (several times approved). The neighbors recently submitted a building application aiming for slightly higher eaves and knee wall heights—this will serve as a reference for us.

For roof option 1 (22–26 degrees pitch): ridge height max. 8 m (26 ft) (or 8.15 m / 27 ft), eaves height max. 4.0 m (13 ft) (or 5.20–5.30 m / 17–17.5 ft), knee wall max. 115 cm (45 in) (or 2.20–2.30 m / 7–7.5 ft)

For roof option 2 (33–44 degrees pitch): ridge height max. 10.5 m (34 ft), eaves height max. 3.5 m (11.5 ft), knee wall max. 40 cm (16 in) (exceptions probably possible but no figures known)

Definition of eaves height: Top of rough ground floor slab to intersection of exterior wall with the bottom edge of the rafters

Definition of knee wall: Top of rough attic floor slab to intersection of exterior wall with the bottom edge of the rafters

Client Requirements

Architectural style, roof shape, building type: a new build that does not look like a typical new build

Basement, floors: no basement (high groundwater level, no living space planned underground), two full stories (which are effectively possible due to generous exceptions from the development plan)

Number of people, age: my mother (70+), my husband and I (late 30s), 2 cats, 1 dog, 1 child planned

Space requirements on ground and upper floors: On the ground floor a self-contained apartment for my mother and kitchen / living / dining / utility for us;

Office: 2 offices (both approx. 50% and 80% remote work)

Guest stays per year: about 2–3 weeks

Open or closed layout: open on the ground floor

Conservative or modern building style: conservative

Open kitchen, kitchen island: yes to both

Number of dining seats: 6–8

Fireplace: yes (gas fireplace)

Music/sound system wall: no

Balcony, roof terrace: balcony would be nice

Garage, carport: spacious double garage

Utility garden, greenhouse: rather no

Other wishes / special features / daily routine, including reasons why some things are desired or not:
  • Covered terrace / loggia / outdoor seating with reliable but as discreet as possible insect protection (lakeside location, regular mosquito issue) & fireplace (probably gas as well)
  • A rather unpopular opinion here, but we explicitly do not want roller shutters or venetian blinds. We currently have them despite many south-facing windows and never use them (feels like a vault). Instead, we plan air conditioning (powered by photovoltaics) and larger trees.
  • Gas stove (I just can’t get comfortable with induction)
  • Washing machine & dryer on the upper floor
  • In one office, a small niche for an exercise bike (turbo trainer)

House Design

Who designed it: DIY

What do you like most and why?

- Style inspired by classic American Colonial architecture

- Living area centered around the fireplace

- Porch with insect protection, fireplace & privacy

- Kitchen island with plenty of workspace

- Small “secondary kitchen” to temporarily hide dirty dishes / cooking mess

What do you not like? Why?

I wouldn’t exactly say “dislike,” but we have doubts about the following points:
  • Passage between garage and house might be too narrow?
  • Entrance and staircase possibly not spacious enough?
  • Staircase: can’t properly design it in the software, but according to a stair calculation tool it should work. Is the space requirement adequate? Are the asymmetrical runs a problem?
  • Bedroom in the self-contained apartment is borderline small
  • Bathrooms: enough space?
  • Utility/technical room: large enough?
  • Could a mechanical ventilation system with heat recovery possibly be installed in the crawl space attic?

Personal price limit for the house, including fittings: we’re budgeting €3,000 per m² plus additional costs and landscaping, but have significant equity and thus some flexibility upwards; also plan a lot of personal work.

Preferred heating technology: heat pump with geothermal probe

If you have to give up something, which features/finishes
- Could be sacrificed: balcony
- Cannot be sacrificed: no compromises on the self-contained apartment

Why is the design like it is now?

We originally wanted to buy a house with old-style charm but found nothing suitable. Although we like modern, minimalist architecture, it’s not for us personally.

I’ll help a bit with the images.


Site plan: pink outline of the plot with red shaded building area.


Floor plan of a single-family house with garage on the left, yellow walls, rooms like living, kitchen, bathroom.


Second floor plan: bedroom, bathroom, ensuite, office, living room, balcony, children's room.


3D render: white houses on grass; interior views of kitchen and living room in a bright style.


3D rendering: white houses with garden; interiors: living room and kitchen.


North, west, east and south views of a single-family house with garage, windows and trees.


Architectural drawing of a large house with garage, trees and facade views (north, west, east, south).


3D model of a multi-part house on green plot with outbuildings; facade view.
K a t j a28 Jan 2025 06:21
CornforthWhite schrieb:

If the space is too tight, then there simply won’t be a parking spot on the property, just a path alongside the neighbor’s lot leading to the entrance of the secondary apartment and a hedge for privacy.
Having two access points will take away your peace and privacy on the property. It’s not just about the parking spot, but especially the path along your terrace. The delivery person is always running there with packages to the front door. Visitors, caregivers, or cleaning staff are constantly ringing the doorbell as well.

Regarding the fireplace:
Sorry, but I have to point out the absurdity of the situation once more. It’s exactly where you’d expect a great view of the garden and where everyone installs large glass doors, yet you want to put in a solid wall with a fireplace. Besides the loss of natural light, the path is also blocked. It’s just not worth it.
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kbt09
28 Jan 2025 07:21
After checking several times, I'm still not entirely clear which property we are talking about.


Cadastral map: magenta outline of a property labeled 'our property'.


I initially thought it was the one outlined in purple, and 497/9 is basically the second street to the north, which also provides access to the main house entrance. On the right is the granny flat with its parking space and terrace.

I don’t understand the text "our property" and the small blue box at all right now.
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CornforthWhite
28 Jan 2025 07:41
kbt09 schrieb:

After checking several times, I’m still not entirely sure which plot of land we are talking about.


I actually thought it was the one outlined in purple, and 497/9 is basically the second street to the north, which also provides access to the main house entrance. On the right is the granny flat with parking space and terrace.

I don’t quite understand the text "our plot" and the small blue box right now.


No, it is the corner plot; otherwise, I wouldn’t have labeled it “our plot.” The one outlined in purple belongs to the neighbor and clearly isn’t part of our house design according to the floor plan. The site plan screenshot is from the neighbor’s building permit / planning application, and I used it because it already shows the future neighboring house to the north and the neighbor’s house to the west on 500/5 correctly. The site plan I have is somewhat outdated, and I preferred to use a correct and to-scale representation rather than sketching on the plan myself. Sorry for any confusion this caused.

The blue box represents the potential parking space for the granny flat, accessible from the other street to the south. The garage for the main house, however, would be accessed from the street to the west.
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CornforthWhite
28 Jan 2025 07:52
K a t j a schrieb:

The double access takes away your peace and privacy on the property. It’s not just the parking space that matters, but especially the path along your terrace. The delivery person always runs along there with packages to the front door. Visitors, caregivers, or cleaning helpers also constantly ring the doorbell.


Have you also considered the access route to the separate apartment coming from the other purple-bordered plot? “Along the terrace” makes me think there might be the same misunderstanding here. Even with the actual layout, I can imagine that the parking space for the separate apartment might be annoying, but the path to the apartment along the eastern neighbor’s fence, with appropriate privacy planting, seems rather unproblematic to me.
K
kbt09
28 Jan 2025 07:54
But the entrance to your house is really quite confusing. And somehow, the porch concept also seems like a scattered effort.
C
CornforthWhite
28 Jan 2025 07:55
K a t j a schrieb:

Regarding the fireplace:
Sorry, but I have to emphasize again how absurd this situation is. Exactly where you would expect a wide opening to the garden and where everyone installs large glass doors, you want to build a massive wall with a fireplace. Besides the loss of light, it also blocks the access. It’s just not worth it.

I would prefer to postpone the fireplace discussion until after we have met with the fireplace specialist on Saturday.