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

Created on: 29 Dec 2024 00:08

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

hanghaus202329 Dec 2024 13:10

#13

You still have room for improvement. The neighbors’ houses are higher. You have plenty of excavation material leftover from the basement. Raise the house and spread the excavation soil across your property. That way, you’ll also get more light in the granny flat.

My granny flat is 80 m² (860 sq ft) and is located on the ground floor and first floor. I wouldn’t even have dared to offer the basement to my in-laws.

Is it worth it?

You can deduct a maximum of 40/190. Don’t forget that the rent must be declared for tax purposes.

hanghaus202329 Dec 2024 13:21

#14

Here is a post from someone who wants to realize something similar.

https://www.hausbau-forum.de/threads/eckgrundstueck-mit-einliegerwohnung.48277/

There are already quite good suggestions without a basement.

nordanney29 Dec 2024 13:33

#15

Such a granny flat is only worthwhile if you are located near a university or actually building in or very close to a major city. Otherwise, it will always remain a pure burden for family use, as it is hardly rentable to outsiders.

From a tax perspective, it only makes sense if you are already quite old. Once the depreciation allowance (AfA) is fully used, it hardly pays off anymore—unless you are approaching retirement and no longer need deductible expenses. Considering the combination of the apartment’s quality and the cost-benefit ratio (tax-wise), I would actually find it too expensive.

njAiiii29 Dec 2024 13:35

#16

SoL schrieb:

Well, giving only 6m² (65 sq ft) of bedroom space to the older person in a 200m² (2,150 sq ft) home is… borderline. Take a few square meters from the living room of the granny flat.

Fair point. Why did we plan it differently so far? The bedroom was really intended just for sleeping, maximizing the space in the living room and kitchen, also considering the lighting.

ypg schrieb:

I can’t contribute anything about the planning phases.
Regarding the floor plan: there are no major flaws. Personally, I’m not a fan of a long, narrow pantry. I would rather skip the pantry and design the kitchen more generously and comfortably.

What minor flaws would you say there are? We would use it as a pantry/storage room and not put everything in the basement by default.

ypg schrieb:

I rather have a problem accepting the granny flat as it is.

I don’t see the “together” or “separate” issue just because of the separate outdoor stairway. There’s a real difference between an internal stairway and an outdoor one—especially for an older person who might take longer on stairs and need resting spots, which could encourage them to stay inside the apartment and avoid the stairs.
Also, the exterior view suggests an outlook, but if you consider the basement unit’s location, an average-height person inside can only see a concrete wall. The terrace strip may be long and therefore large, but it doesn’t change the fact that it’s an unattractive 2-meter (6.5 feet) wide strip, 2 meters (6.5 feet) below ground level.

There will definitely be two separate entrances. So it’s not really “together” but more “not alone” and in very close proximity. One idea was to move the stairway forward and add landings here and there. Suppose we can raise the house by 60cm (2 feet) and need 2–3 steps at the front; then we would need three fewer steps for the stairway down. That would be 15 - 3 = 12 steps over about 6 meters (20 feet), possibly over 5 meters (16 feet).

ypg schrieb:

I pick up the word “emergency” and say: it’s an emergency (makeshift) apartment. Who would want to rent that?

Of course, it’s just opinions. Is it really that terrible? If I were single and valued closeness to nature, I probably wouldn’t mind it as much. Compared to alternatives in our area, this basement unit isn’t really among the worst. Nearby there are several granny flats that are partially buried. Hardly any of them even have a terrace or garden access.
Regarding willingness to rent: what difference would it make? Should we move the granny flat completely to the ground floor?

ypg schrieb:

About the sleeping area—no need to say much. In my opinion, I would put the bedroom on the lower end of the plan, and the kitchen near the entrance. That way, the underground terrace strip can be shorter and designed with a slope to make it wider and more attractive with planting toward the garden. Does that make sense?

If I understand you correctly, “lower end of the plan” means next to the bathroom for you. I tried a quick sketch with simple paint skills without enlarging the space. Did you mean something like this?

Detailed floor plan of a house with living room, kitchen, hallway, cellar rooms and terrace

The terrace strip can be designed however we want. According to the architect, we need to support both the house and the terrain there. It is more cost-effective not to have the strip run all the way to the end of the house. We followed the approach shown in the two additional attachments.

Exterior view of a modern white multi-family house with terrace and garden

Exterior view of a modern house with white facade, terrace and garden.

ypg schrieb:

That’s a joke.

It’s multifunctional: workspace (though clearly too large for that), guest room (which is very rarely used alone), storage (books, odds and ends), and as the basic concept eventually converting it into a bedroom in 30+ years. Why is that idea so bad?

hanse987 schrieb:

I would rather choose the city center. And I have to say that I’m not a city person, but for me that basement apartment is out of the question.

Hello Hanse987,
Thanks for sharing your opinion. What exactly wouldn’t work for you? Does the apartment have to be taken out of the basement? Would it help to raise the basement? What about the design is problematic? It’s hard to get actionable feedback from pure rejection that helps us improve the situation overall.
Do you have a granny flat yourself, or have you ever lived in a basement and speak from experience?

In principle, we wouldn’t mind working from the basement. Because we want to keep the units separate, however, we have struggled with suggestions that would make a granny flat on the ground floor much more comfortable. So far, the only option would be to place the granny flat on the northeast side of the house. That would be narrow and dark and would require a complete redesign of both the ground and upper floors. Unfortunately, we found little to no inspiration in standard floor plans from prefab house builders. Many…

njAiiii29 Dec 2024 14:13

#17

K a t j a schrieb:

Looking at your design, these all seem like compromise solutions that are never really ideal. A basement apartment – no one wants to live like that. The slope is too gentle for a genuine basement floor, and the stairs are already an obstacle for people over 70 – especially in winter. Having the living area accessible only through the kitchen is inconvenient, and entering the pantry through kitchen cabinets is even worse.

Why is having the pantry through the kitchen inconvenient? Because the door wears out? On the northeast side, we have the neighbor. There’s an old brick bungalow there, semi-pleasant to look at. We could remove the pantry and put the kitchen completely into the corner. Then we would have to reconsider storage space.
How would you access the living area then? Another door right next to the kitchen door leading to the living room, and recess the wall for that? Then you would have a small corner or pillar there and see the staircase. We find that less appealing.

K a t j a schrieb:

If the basement apartment really has to be included, you should design it so that people truly want to live there. Imagine having to move in there next year! That means, in my opinion, ground level with plenty of light and air, without excavations – for example as an extension. The space you are currently using for excavations is too small to really let in light to the basement apartment and have a decent terrace, but too large to use the garden behind effectively. You might as well build on it.

So you would give up the basement and put the apartment on the ground floor? What conditions would have to be met for the basement apartment to remain in the basement?

hanghaus202329 Dec 2024 14:21

#18

njAiiii schrieb:

So you would skip the basement and put the granny flat on the ground floor? What conditions would need to be met for the granny flat to stay in the basement?

The basement remains the basement. If it can be designed like in the pictures, that would help. But the floor plan is still not good.

Living space in the basement is expensive. The exterior work costs a lot of money.

How high is the groundwater level?

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

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