ᐅ Floor plan, house layout EFW 150 m², basement with granny flat – feedback welcomed

Created on: 29 Dec 2024 00:08
N
njAiiii
Hello dear forum,

we have been quietly following along for some time, knowing that we will eventually build our own home. Thanks in advance to everyone who regularly posts here and shares their knowledge. This is very helpful for laypeople like us. We already appreciate you taking the time to focus on our project and critically review it. The moment is getting closer. The plot is secured. It is located near a protected landscape area with a gentle slope. The soil report indicates occasional hydrostatic pressure.

How will we proceed?
  • Purchase plot, conduct soil survey
  • Position and design house on plot with architect (phases 1-3)
  • Invitation to bid for general contractor and individual trades for interior work, followed by comparison
  • Construction with expert supervision

What do we want to build?
  • Single-family house with separate apartment (for family and mainly for tax reasons, especially for the various depreciation options, therefore also with QNG [quality seal for sustainable building])
  • Why basement? To maximize garden space, add storage area, and supposedly take advantage of the slope

Development Plan/Restrictions
Plot size: 650m2 (7000 sq ft approx.)
Slope: Yes, gentle (scale 1:250, see elevation in attachment; 1m (3.3 ft) over approx. 10x11m)
Floor area ratio (FAR): No formal development plan, approx. 220m2 (2368 sq ft) floor area possible after approval by building authority
Building coverage ratio: No formal plan, approx. 220m2 (2368 sq ft) floor area possible
Building setback lines and boundaries:
- 5m (16 ft) from the street
- 3m (10 ft) from neighboring properties
Edge building: On both sides and opposite along the street
Number of parking spaces: Probably 3 required (we could move the house back so parking is directly in front)
Number of floors:
- Technically 2 floors,
- But visually aligned with surrounding buildings, so a 1.5-story appearance desired
Roof type: Gable roof with 30-40cm (12-16 inches) overhang
Style: Modern
Orientation: Southeast, but surrounded by many mature historic trees from east to west along the plot boundary
Maximum heights/restrictions: Neighboring buildings, street alignment
Additional requirements: For flat roof, 1m (3.3 ft) setback from street and sides

Homeowners’ Requirements
Style: Modern
Roof pitch:
- Gable roof between 25-33°
- Originally flat roof to the left neighbor, now gable roof preferred for budget, maintenance, and required setbacks
Building type: Single-family house with separate apartment
Basement: Yes
Stories: "1.5"
Knee wall height: 1.90m (6.2 ft) (no official requirement); we want to minimize sloped ceilings
Number of occupants: 4 (2 adults age 40, 2 children aged 4 and 1) + 1 family member for the separate apartment
Space requirements for ground floor (GF) and upper floor (UF):
- Originally 141m2 (1519 sq ft) net usable area without circulation space
GF:
- Open living/dining area with pantry
- Office (possibly bedroom later in life)
- Shower bathroom
- Entrance hall
UF:
- 2 children’s rooms from 13m2 (140 sq ft) each
- Bedroom as small as possible + walk-in closet with standard wardrobes
- Bathroom with T-layout, shower, tub, toilet
- Second workspace
Office: Family use or home office?
- Home office twice a week, about 3-4 days out of 5 at home
Visitors per year: One overnight guest per quarter
Open or closed architecture: Open
Conservative or modern construction: Modern
Open kitchen with island: Yes
Number of dining seats: 4-6, extendable up to 10 (2m (6.5 ft) table extendable to 3m (10 ft))
Fireplace: No
Music/sound system wall: No
Balcony, roof terrace: No
Garage/Carport: Prefabricated garage 3x7m (10x23 ft), possibly 3x9m (10x30 ft)
Utility garden, greenhouse: Yes (vegetables, fruit, cistern)
Additional wishes / special features / daily routine, including reasons why some options are excluded:
  • We are an early riser (Larch + Owl), so with two kids (maybe 3 someday), a second shower bathroom is essential
  • Open living/dining area as the heart of the home: We cook a lot and enjoy it; this is the social center
  • Standard sizes where possible (wardrobe widths, doors, windows, house shape, etc.)
  • If reasonable, include basement
  • Covered walkway from house entrance to garage (still discussing presentation; garage likely needs attic height >3m (10 ft), which may require an easement on the boundary)
  • We will very likely install a “glass awning” on the terrace afterwards
- Our priority list:
  • Photovoltaic system
  • Air-to-water heat pump
  • Ventilation system
  • Open living-dining area (L-shaped)
  • Light-filled rooms
  • Maximum knee wall height
  • Maximized ceiling height on GF/UF
  • Living/dining area with floor-to-ceiling windows
  • Daylight bathrooms
  • Dining table 2m (6.5 ft) long (extendable to 3m (10 ft))
  • Modern look with individual accents
  • Low roof pitch
  • Interior doors at least 1m (3.3 ft) wide
  • Shower bathroom on the ground floor
  • Walk-in closet
  • Pantry also as storage room
  • Staircase not directly at entrance door (airlock/dirty corridor)
  • Office potentially usable as bedroom
  • Kitchen island at least 2m (6.5 ft) wide
  • Flat roof dormer and/or bay window
  • Second workspace (bedroom, landing, or similar)
  • Bathroom with T-layout
  • Daylight in landing
  • Basement apartment
  • Separate entrance to basement apartment
  • Lift-and-slide door
  • Maximize southwest garden area
  • Partially covered terrace
  • View axis from hallway to garden
  • Daylight in walk-in closet
  • External access to basement
  • Laundry chute
  • Window seat
  • Basic smart home features

House Design
Designer:
  • Architect, phases 1-3

What do you particularly like and why?
  • The ground floor overall; many wishes fulfilled, some highlights
  • Bedroom and walk-in closet; probably adding a door in between later
  • Landing staircase, view axis, kitchen windows, entrance hall

What do you dislike and why?
  • GF office faces southwest instead of east or southeast
  • GF living room: fixed glazing towards southwest too small
  • GF living room: lift-and-slide door too large, couch doesn’t fit well
  • GF living room: considering glazing the entire wall
  • GF corridor quite long
  • UF sizes depend on GF; rooms (except bedroom and closet) are rather large
  • UF bedroom faces southwest instead of north
  • UF considering all windows floor-to-ceiling except stair and landing for light and appearance
  • Garage not directly attached to house due to access to separate apartment
  • Separate apartment quite complex
  • Initially we drafted an "L-shaped" house similar to post here, but could not solve circulation areas properly; currently seeing them as a “necessary evil.”

Price estimate by architect/planner: $3,300 - $3,500 per m2 (approx. $307 - $325 per sq ft), total approx. $700,000 - $800,000 plus additional costs
Personal maximum budget including fittings: $750,000 plus additional construction costs
Preferred heating technology: sustainable + underfloor heating (comfort); geothermal possible but based on current research not cost-effective

If you had to give up something, which features/finishes?
-cannot give up:
  • Separate apartment (for family and tax benefits)
  • Office (need a dedicated setup at least for one person; also for guests and as retreat)
  • Two children’s rooms

-could give up: probably everything else

Why does the design look like it does now? For example:
Standard plan from designer? No; from architect
- We shared all our ideas and preferences with the architect and discussed them beforehand
- This is the second iteration; earlier option had flat roof dormer with southwest children’s room, which we discarded; roof pitch probably 25° now
Which wishes did the architect implement?
  • Most of them, but not all possible

What do you think about it, especially focusing on current pain points:
  • Actually, our space requirements are smaller, but we cannot fit that on the ground floor to align with upstairs (difference about 10-15 m2 (110-160 sq ft)); kids’ rooms and circulation spaces including landing could be smaller
  • Window area not yet optimal in living/dining, office, and large upstairs living area; considering 1.10m (3.6 ft) fixed glazing and 2.50m (8.2 ft) lift-and-slide door
  • House feels somewhat "buried"; considering raising overall or at least GF + UF by 40-80cm (16-32 inches) above ground level
  • The whole topic of “house/garage connection,” earthworks, and plot landscaping is very complex and time-consuming
  • No external blinds (raffstores) possible on landing due to knee wall and roof
  • Separate “dirty corridor” and staircase; could be a minor disadvantage for aging, might make separate UF rental impossible in future

Due to the maximum number of attachments allowed, we couldn’t add an aerial photo of the tree cover. There are three large deciduous trees directly to the southeast and on the southwest side about two chestnut trees and around 15 pines from the 1950s. We have no worries about summer heat protection 😉 – on the contrary: enlarging the house footprint would cost us garden and especially daylight.

Feel free to ask any questions.
We look forward to your feedback and thank you in advance.
Architectural drawing of a facade view of a house with dimension markings

Site plan of building plot with residential house, driveways, tree lines, and property boundaries

Front view of a house with roof, windows, and entrance door – architectural drawing

Modern single-family house exterior with dark roof, light facade, and large windows

Cross-section of a two-story house with gable roof, windows, basement, and terrace

Modern house side with dark gable roof, light grey facade, three windows, and entrance ramp

Section view of a multi-story house with stairwell, roof, and dimension lines

Floor plan of house upper floor with hallway, bathroom, bedroom, office, and 2 children’s rooms

Floor plan of single-family house: living/dining, kitchen, office, hall, corridor, WC/shower, garage

Floor plan of house with basement, separate living area, kitchen, bedroom, bathroom, and terrace
11ant30 Dec 2024 14:08
njAiiii schrieb:

We looked at countless solutions with a basement apartment in the area. The visual and spatial separation appeals to us conceptually.

As laypeople, no matter how much we tried to draw ourselves, we couldn’t make progress beyond a certain point without professional software and various detailed inputs regarding walls, ceilings, etc. Then we involved an independent architect and discussed the inputs (longlist, basement apartment including some ideas and photos). From the start, we asked the architect to maximize the ceiling height. That has not happened to this day. Instead of discarding the design, we obviously got stuck trying to optimize within this framework. Regarding the basement apartment, the focus was on how to fit a compact bedroom and make the living area as large as possible.
The result: many compromises, the basement apartment as it is.
Conclusion with your input so far: we’ll go back to the drawing board and try a completely different design.

That will be the best approach. But then the architect should also completely discard the old requirements specification, otherwise it won’t be a genuine restart. No preset demands for a supposedly clever “jack-of-all-trades” height placement.
njAiiii schrieb:

We always assume one person for the basement apartment who is in the final stage of life. Now that means less than 30m2 (about 320 square feet) in the city center on the 5th floor is out. At some point, it means Grandma or Grandpa moving out of a house that is already too large.

If the parents-in-law’s house is too big, the individual parent could share a household with them. That way, they don’t have to pass away in the “correct” order just to free up the basement space, whose “bedroom” is an alcove bed that is not suitable for seniors even if they are in their seventies and still active. Thus, the basement apartment is not suitable as a living space for a senior themselves, only for a caregiver. Raising the basement apartment 60 cm (2 feet) or so to be able to look out of that hole certainly doesn’t fix this flawed planning. It’s better to build an above-ground guest room where the three (step)parents can alternatively retreat for a grandchild’s visit from their shared household. A suite with a bathroom, which also helps solve the morning bathroom traffic jam when the kids are teenagers.
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Y
ypg
30 Dec 2024 14:33
njAiiii schrieb:

That’s exactly why we place the kitchen on the east side.
In summer, it’s simple: just the terrace.
njAiiii schrieb:

In spring, autumn, and winter, you spend the day with the kids somewhere around the living room / dining area / bay window.
njAiiii schrieb:

If that works, okay. But then the living room is on the east side and noticeably darker, especially if it remains separated in an L-shape.

I think we are talking past each other.
Or I currently don’t understand your reasoning.
The dining area and kitchen should benefit from plenty of natural daylight. Exactly. The dining table is already well placed where it is. However, if you stand in your kitchen from the afternoon on, it needs artificial lighting. Your kitchen window is not big enough for that. Your terrace is on the south side by the sofa, so currently it’s quite a long way from the refrigerator to the grill. During the darker seasons it gets dark from the afternoon anyway. So, you have no chance to enjoy daylight on the sofa, and you need less there. It can even be distracting when watching TV. So you put the kitchen in the brightest corner by the terrace because the sofa needs the least daylight throughout the year.
njAiiii schrieb:

If we have a net depth of 120,

But you don’t. You have 115 rough wall-to-wall (RBM), minus plaster and tolerances, which leaves just over 100. With baseboards and some circulation space between furniture and wall, you have less than 100cm (39 inches) left.
N
njAiiii
30 Dec 2024 16:49
Ok. Makes sense. Thanks for explaining.

Assuming the granny flat is completely omitted. What would be your comments? Swap the kitchen and living room. Rethink the pantry. Anything else?
K a t j a30 Dec 2024 17:20
njAiiii schrieb:
Ok. Makes sense. Thanks for explaining.

Assuming the granny flat is completely removed. What would be your comments? Swap the kitchen and living room. Rethink the pantry. What else?
This question comes up several times, which in my opinion is pointless. The granny flat is essential. If it is removed, you have to start the design from scratch – which you are planning to do anyway.
M
MachsSelbst
30 Dec 2024 17:51
Have you ever lived in very close quarters with these family members for an extended period?
People don’t get any easier to live with as they age, and often things can go spectacularly wrong, even if you got along great before...
H
hanghaus2023
30 Dec 2024 19:09
njAiiii schrieb:

Assuming the granny flat is dropped. What aspects of the layout on the ground floor / upper floor could be improved?


You’ve already received quite a few answers. So here’s a fresh take.
njAiiii schrieb:

I’m trying to understand this based on the price per square meter. Simplified: 40m² (430 sq ft) granny flat at 3000 EUR / m² equals 120k plus stairs 20k plus land 25k? Plus excavation and disposal (which I consider already accounted for with the basement) and possibly some buffer = 165 - 190k. Is that about right?
That would effectively be nearly 4-5k/m².


You’ve captured that quite well. However, the retaining walls around the stairs and the terrace are significantly more expensive.
njAiiii schrieb:

Attached is the summary.


If you decide to build without a basement, the soil report must be updated accordingly.

Hopefully, raising the house is no longer under consideration. But it can be a reasonable solution, as the neighbors have done. In that case, the house would need to be set further back on the lot, like the neighbors.

I once lived in a basement apartment myself. After three months, I was able to afford something better.

As I mentioned, I have a granny flat that my in-laws have lived in for over 20 years. It works very well. They are now both in need of care but can still live here. We installed a stair lift since the bedroom is on the upper floor. Our lot also has a slight slope—about 1m (3 ft) across the property. That makes it difficult to bring much daylight into the basement, at best you see the grass surface.