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

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.

njAiiii schrieb:

+ Basement apartment (for family use and for tax reasons)

At least it’s honest to say the main reason is tax benefits. But the renovation and finishing costs still have to be paid. Isn’t that a flawed or naive calculation? First of all, you need invoices in order to claim tax deductions, right? You don’t get a basement apartment or a finished cellar with shafts for free!

It’s less suitable for renting out because it’s very visible in the garden.

At least the statement is honest that the reason is to make it financially worthwhile from a tax perspective. But the finishing work and so on still need to be paid for. Isn’t that a flawed or naive calculation? First of all, you need invoices in order to claim tax deductions, right?! You don’t get a granny flat or a finished basement with the necessary shafts for free!

Hey ypg, thanks for the quick reply.

The thought process goes as follows: The granny flat is intended to be included so that the older generation can initially raise the kids and later not be left “alone.” Currently, on one side, there is only one person. Even though it can’t be planned perfectly, it’s likely that the other side will experience a similar situation but delayed in time. It’s all quite far off, but that is one of the reasons.

Of course: payment has to be made now. Based on the construction costs and additional expenses we anticipate so far, it “pays off” for us in the long run, especially when combined with family, kids, emotions, and depreciation. That’s why the granny flat is not so easy for us to dismiss. But we are open to all viewpoints and arguments. Our architect roughly indicated what additional efforts would be involved. We have compared our assumptions for the entire construction project.

It’s less suitable for rental because it is very exposed in the garden.

During the next 20 years, it will almost certainly be used only by the family. How to separate the garden for rental to outsiders afterward has not been finally discussed yet. We’re sure solutions will be found. If necessary, only the unit would be rented out.

As a follow-up, here is why we have only proceeded up to design phase 3 so far and how long the "dough" has been resting.

As laypersons, we only discovered this forum relatively late. Until then, we felt well advised elsewhere through design phase 3. The dough has been resting for several weeks now. This was also due to setting and reducing the "wish list" as well as between the first iterations of the drafts. In theory, we could still proceed to design phase 4 with the architect.

Perhaps a bit more context on the draft iterations is helpful:

Draft 1 included a door on the ground floor along the living room wall, so you could enter either the living room or the kitchen. However, this nearly eliminated the space available for furniture in the living room. We don't have a huge TV and only use it occasionally. But having the doors right next to each other didn’t make much sense to us. The sightline from the living room towards the basement stairs was also rather questionable. The compromise was to walk "through the kitchen." Ideally, we would prefer a clean sightline—obviously. But that would make the kitchen too small.

There was also the idea of swapping the living room and kitchen and placing the pantry on the back wall of the study. That didn’t really convince us either in the end.

Upstairs, we considered adding a dormer due to the orientation of the children’s rooms. However, this was very inconsistent with the ground floor layout.

Good morning, I have a question about the window heights! They are important to me. We messed them up, and anyone still in the planning phase can avoid having a lintel that is disproportionately large and disrupts the appearance. What ceiling height was planned? Is it correct that the windows are 2.08 m (6 ft 10 in) tall!?

njAiiii schrieb:

Number of people: 4 (2 adults 40 years old, 2 children (4, 1)) + 1 family member for the granny flat

How old is the older person?