ᐅ Floor Plan Design for a Single-Family Home with a Secondary Apartment
Created on: 6 Mar 2024 00:38
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Sleepwalker1
Dear forum members,
I have been following this forum for some time now and have already gathered a lot of helpful information for our planned house construction. Many thanks for that!
We have now finalized our floor plan, and I would appreciate your expert feedback on our designs.
P.S. Since the location and orientation of the house and garage on the corner plot are quite fixed and conform to the development plan, my main concern is the room dimensions and whether the layout, in your opinion, works well in reality. Of course, I am open to any suggestions and improvements.
Thank you in advance!
Best regards
Development Plan / Restrictions
Plot size: 880 m² (9,470 sq ft)
Slope: 3 meters (10 feet) incline from south to north (see attached survey)
Floor area ratio (FAR): 0.4
Gross floor area ratio (GFAR): 0.8
Building area boundaries, building line, and limits: 3 meters (10 feet)
Edge development: Garage directly adjacent to neighbor’s property, up to 9 meters (30 feet) in length
Number of parking spaces: 2
Client Requirements
No basement, 2 full floors
Number of occupants, age: 4 people (2 adults in their mid-30s, 1 toddler, 1 child planned)
Office: occasional home office (2 days per week)
Overnight guests per year: possibly 4–5 times
Open-concept design
Open kitchen with island
Number of dining seats: 8
KfW standard EH 40 compliant (including granny flat)
Potential preparation for a fireplace (installation not allowed due to KfW requirements)
Garage with storage room and carport (also serves as entrance canopy)
House Design
Designer: Architect
What we like: open living/dining area, utility room on the upper floor, storage room with freezer under the stairs, “mudroom” in the technical room, granny flat, half-landing staircase, carport serving as entrance canopy
What we don’t like: possibly the office
Estimated price according to architect: 500,000 €
Personal budget for the house, including fittings: approx. 550,000 € (plus own work)
Preferred heating system: air-to-water heat pump
If You Had to Give Up Certain Details or Extras
Separate walk-in closet, T-shaped bathroom layout
Why the Design Is the Way It Is
Based on our individual preferences and wishes
I have been following this forum for some time now and have already gathered a lot of helpful information for our planned house construction. Many thanks for that!
We have now finalized our floor plan, and I would appreciate your expert feedback on our designs.
P.S. Since the location and orientation of the house and garage on the corner plot are quite fixed and conform to the development plan, my main concern is the room dimensions and whether the layout, in your opinion, works well in reality. Of course, I am open to any suggestions and improvements.
Thank you in advance!
Best regards
Development Plan / Restrictions
Plot size: 880 m² (9,470 sq ft)
Slope: 3 meters (10 feet) incline from south to north (see attached survey)
Floor area ratio (FAR): 0.4
Gross floor area ratio (GFAR): 0.8
Building area boundaries, building line, and limits: 3 meters (10 feet)
Edge development: Garage directly adjacent to neighbor’s property, up to 9 meters (30 feet) in length
Number of parking spaces: 2
Client Requirements
No basement, 2 full floors
Number of occupants, age: 4 people (2 adults in their mid-30s, 1 toddler, 1 child planned)
Office: occasional home office (2 days per week)
Overnight guests per year: possibly 4–5 times
Open-concept design
Open kitchen with island
Number of dining seats: 8
KfW standard EH 40 compliant (including granny flat)
Potential preparation for a fireplace (installation not allowed due to KfW requirements)
Garage with storage room and carport (also serves as entrance canopy)
House Design
Designer: Architect
What we like: open living/dining area, utility room on the upper floor, storage room with freezer under the stairs, “mudroom” in the technical room, granny flat, half-landing staircase, carport serving as entrance canopy
What we don’t like: possibly the office
Estimated price according to architect: 500,000 €
Personal budget for the house, including fittings: approx. 550,000 € (plus own work)
Preferred heating system: air-to-water heat pump
If You Had to Give Up Certain Details or Extras
Separate walk-in closet, T-shaped bathroom layout
Why the Design Is the Way It Is
Based on our individual preferences and wishes
Schorsch_baut schrieb:
This is not a granny flat; it’s a guest room with its own bathroom. 🙂
A granny flat must have a minimum floor area of 23 sqm (248 sq ft) and allow independent household management. And a separate entrance, if I’m not mistaken. So either a private front door or an apartment door from a shared hallway. Here, it simply branches off from the foyer/kitchen/living room/dining room.
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Schorsch_baut6 Mar 2024 09:09To me, it looks more like a home office/guest room is planned on the ground floor, which leads to the guest bathroom. The office on the upper floor will then become the walk-in closet.
C
Costruttrice6 Mar 2024 09:12Why do you need the granny flat? Renting out such a small room is probably difficult. The entrance situation is quite poor. Also, the tenant would have free access to your rooms, plus with the open layout you would always know when the tenant comes and goes.
For 4-5 overnight guests, a granny flat doesn’t really make sense, and permanently accommodating grandma in 13m² (140ft²) including a kitchen is questionable.
If it’s only for the subsidy, I would consider whether the money could be saved elsewhere.
If you drop the granny flat and instead use the space for an office (with a sofa bed) plus a guest bathroom with a shower, the problem of accessing the office through the bedroom would also be solved, and the children’s rooms could be larger. I find 12m² (130ft²) a bit small for the size of the house.
Overall, I find the design pretty uninspired and unloving when it comes to the office, children’s rooms, granny flat, and utility room. There definitely should be more potential to improve.
Others are better informed about terrace planning and ceiling heights.
For 4-5 overnight guests, a granny flat doesn’t really make sense, and permanently accommodating grandma in 13m² (140ft²) including a kitchen is questionable.
If it’s only for the subsidy, I would consider whether the money could be saved elsewhere.
If you drop the granny flat and instead use the space for an office (with a sofa bed) plus a guest bathroom with a shower, the problem of accessing the office through the bedroom would also be solved, and the children’s rooms could be larger. I find 12m² (130ft²) a bit small for the size of the house.
Overall, I find the design pretty uninspired and unloving when it comes to the office, children’s rooms, granny flat, and utility room. There definitely should be more potential to improve.
Others are better informed about terrace planning and ceiling heights.
S
Schorsch_baut6 Mar 2024 09:17The separation is ensured by the hallway, but to qualify for KFW funding, the requirements for a self-contained residential unit must be strictly met. Since last year, compliance is monitored much more rigorously compared to before when funding was distributed more generously and it was sufficient to include a room with a separate bathroom and kitchenette on the building plan.
DIN 4109 regulates the boundary areas between a granny flat (secondary dwelling) and the main residence regarding impact noise, body noise, and airborne sound insulation. This significantly increases construction costs to the point where it may no longer be worthwhile.
(We are currently planning how to accommodate the mother-in-law with us, which is not so simple under the updated funding conditions.) If you are working with architects, they should be aware of this as well.
DIN 4109 regulates the boundary areas between a granny flat (secondary dwelling) and the main residence regarding impact noise, body noise, and airborne sound insulation. This significantly increases construction costs to the point where it may no longer be worthwhile.
(We are currently planning how to accommodate the mother-in-law with us, which is not so simple under the updated funding conditions.) If you are working with architects, they should be aware of this as well.
Let's take a closer look at a realistic secondary apartment.
The toilet window under the shared carport (which landlords might find problematic) and the window of the secondary apartment next to the terrace (which might not appeal to everyone) are two reasons why the secondary apartment fails in terms of location. Who would want to rent that?
Driveway: bridging one meter (3 feet) over 9 meters (30 feet)? I really can’t imagine that at the moment. As I’ve already mentioned, nothing fits in 3D here. Most likely, the garage would need to be shifted up and to the right on the plan...
But back to the secondary apartment: to accommodate a secondary apartment, the unit would need to be enlarged – that means extending the entire house by about one meter (3 feet). This would benefit the living room on the ground floor, which with a room size of 3.88 meters (13 feet) in RBM footage feels too small. Upstairs, the house would have an advantage compared to having small children’s rooms. Of course, because of the stair positioning, everything gets rearranged, probably moving the children's rooms to the right side of the plan and the bedroom to the left.
Since the house already has almost 180 square meters (about 1,940 square feet) — which is not really noticeable because the secondary apartment and the bedroom take up a lot of space — and with the secondary apartment included the budget is already tight due to the extensive earthworks (the house is being built against the natural slope), the secondary apartment and the entire house plan are essentially off the table, meaning it’s basically a dead end. The earthworks required just to have a terrace means creating even more of a slope on the property, making the garden either more costly to make accessible or necessitating terracing, which causes enormous expenses.
By the way, how is that supposed to work? Is the north arrow wrong? A typo? I see something different.
Survey? The draft posted here was created with a common software sold under various brand names. You can input contour lines in it. I have that program, and @kbt09 does too... So this is not a surveyor’s plan!
Furthermore, if the secondary apartment is adjusted in size, then you would have an approximately 2-meter (6.5 feet) long hallway at the front door that is shared. Whether four people would want to put up with that is questionable. Having the utility room serve as an airlock doesn’t really work anymore because you haven’t even reached your main apartment yet. But let it be: the kitchen would have to be adequately sized because the freezer storage is no longer really useful when relocated outside the main apartment.
The staircase needs to be mirrored; then you would gain some value by having the freezer under the stairs. But no more than that will fit under there... The sliding door to the terrace should be accessible from the open side. Currently, it's poorly placed because the island is in front of it.
As for the niches, plenty has been said... either they are deliberately designed as built-in closets or just not properly planned by a layperson.
The chimney will be removed, so it won’t be in the way anymore.
Upstairs: the office can’t serve as a guest room in this form, the children’s room is too small proportionally, the hallway is basically an inverted U if you count the access via the walk-in closet. The windows don’t make sense to me: why does a walk-in closet apparently facing the street or a small utility room have a floor-to-ceiling window? Is it imagined that laundry would be dried on the carport roof?
Overall, I think there’s some confusion here, and this has been presented as a draft.
The toilet window under the shared carport (which landlords might find problematic) and the window of the secondary apartment next to the terrace (which might not appeal to everyone) are two reasons why the secondary apartment fails in terms of location. Who would want to rent that?
Driveway: bridging one meter (3 feet) over 9 meters (30 feet)? I really can’t imagine that at the moment. As I’ve already mentioned, nothing fits in 3D here. Most likely, the garage would need to be shifted up and to the right on the plan...
But back to the secondary apartment: to accommodate a secondary apartment, the unit would need to be enlarged – that means extending the entire house by about one meter (3 feet). This would benefit the living room on the ground floor, which with a room size of 3.88 meters (13 feet) in RBM footage feels too small. Upstairs, the house would have an advantage compared to having small children’s rooms. Of course, because of the stair positioning, everything gets rearranged, probably moving the children's rooms to the right side of the plan and the bedroom to the left.
Since the house already has almost 180 square meters (about 1,940 square feet) — which is not really noticeable because the secondary apartment and the bedroom take up a lot of space — and with the secondary apartment included the budget is already tight due to the extensive earthworks (the house is being built against the natural slope), the secondary apartment and the entire house plan are essentially off the table, meaning it’s basically a dead end. The earthworks required just to have a terrace means creating even more of a slope on the property, making the garden either more costly to make accessible or necessitating terracing, which causes enormous expenses.
By the way, how is that supposed to work? Is the north arrow wrong? A typo? I see something different.
Sleepwalker1 schrieb:
Slope: 3 meters (10 feet) incline from south to north (see attached survey)
Survey? The draft posted here was created with a common software sold under various brand names. You can input contour lines in it. I have that program, and @kbt09 does too... So this is not a surveyor’s plan!
Furthermore, if the secondary apartment is adjusted in size, then you would have an approximately 2-meter (6.5 feet) long hallway at the front door that is shared. Whether four people would want to put up with that is questionable. Having the utility room serve as an airlock doesn’t really work anymore because you haven’t even reached your main apartment yet. But let it be: the kitchen would have to be adequately sized because the freezer storage is no longer really useful when relocated outside the main apartment.
The staircase needs to be mirrored; then you would gain some value by having the freezer under the stairs. But no more than that will fit under there... The sliding door to the terrace should be accessible from the open side. Currently, it's poorly placed because the island is in front of it.
As for the niches, plenty has been said... either they are deliberately designed as built-in closets or just not properly planned by a layperson.
The chimney will be removed, so it won’t be in the way anymore.
Upstairs: the office can’t serve as a guest room in this form, the children’s room is too small proportionally, the hallway is basically an inverted U if you count the access via the walk-in closet. The windows don’t make sense to me: why does a walk-in closet apparently facing the street or a small utility room have a floor-to-ceiling window? Is it imagined that laundry would be dried on the carport roof?
Overall, I think there’s some confusion here, and this has been presented as a draft.
N
nordanney6 Mar 2024 12:35SoL schrieb:
And a private entrance, if I’m not mistaken. So either a separate front door or an apartment door off a shared hallway. Here it simply branches off from the hallway/kitchen/living room/dining area. Yep. Currently, this does not qualify as a separate dwelling unit for the KfW.
For me, as a financer, the budget is interesting. 170 m² (1,829 sq ft) with an estimated €500,000 = €2,940/m² (plus contingency). Does that include additional construction costs? Does it include carport/external landscaping? Are earthworks on the slope accounted for? Is this gross or net?
I have a big question mark here—unless there is substantial owner labor involved (and the furnishings are inexpensive).
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