ᐅ Multigenerational house (two households) on an existing plot of land
Created on: 16 Feb 2021 21:37
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EineEULEGood evening everyone,
I have been considering this for a while now, and I would like to start defining things more concretely. Naturally, I haven’t thought through every detail yet, but I do have a rough concept. I would appreciate it if you could review it as well to check whether, due to my lack of building experience, I might have some fundamental misunderstandings or if there are certain topics I should approach differently from the start.
Situation:
I am fortunate that my family already owns a building plot of 650 square meters (7000 square feet). It was developed about 20 years ago, is located at the end of a dead-end street (private road, already paid for), and is basically just waiting to be built on. I have obtained the zoning plan from the early 1980s, which naturally imposes certain restrictions. To what extent exceptions are possible is still beyond my construction-related knowledge — if they are necessary at all.
Some key data: floor area ratio 0.4; floor space index 0.5; one full story; roof pitch 25-35 degrees Celsius (77-95 Fahrenheit); gable and hip roofs permitted; building height 3.50 meters (11.5 feet), measured from the ground floor finish level to the top of the rafter at the outer wall at roof section.
The plot is trapezoidal, approximately 30 by 20 meters (100 by 65 feet). I can prepare a sketch if needed.
I would basically build on my own, which financially should not be a problem given my income. An initial consultation with a mortgage advisor based on my first, naively estimated budget of around €500,000 (about $545,000) did not raise any major concerns, especially since I have significant equity and the plot is quite expensive, which obviously increases the overall value.
What is to be built:
The basic idea is to completely finish the larger unit to make it immediately habitable, while the smaller unit will be kept in reserve. I am not sure to what extent finishing is necessary there to maintain the building fabric. There definitely won’t be a bathroom, except for any required connections.
Of course, I have looked for inspiration among the usual prefab house providers for possible realizations. I am not sure how welcome direct references or links are here.
My question: with these key data, do I already have a fundamental planning mistake at this stage? Is a budget of about €450,000 (roughly $490,000) plus 10% contingency (for the first construction phase only) totally unrealistic? I have of course browsed through this forum seeing price per square meter figures, but I have no idea how these two construction phases would influence the costs. I understand costs vary drastically depending on fittings and finishes — but hopefully, during planning, one can get closer to more reliable values.
My approach now would be, after your plausibility check, to find a possible floor plan in the prefab house sector and based on that evaluate other building types or discuss further with the prefab house provider.
Thanks in advance 🙂
I have been considering this for a while now, and I would like to start defining things more concretely. Naturally, I haven’t thought through every detail yet, but I do have a rough concept. I would appreciate it if you could review it as well to check whether, due to my lack of building experience, I might have some fundamental misunderstandings or if there are certain topics I should approach differently from the start.
Situation:
I am fortunate that my family already owns a building plot of 650 square meters (7000 square feet). It was developed about 20 years ago, is located at the end of a dead-end street (private road, already paid for), and is basically just waiting to be built on. I have obtained the zoning plan from the early 1980s, which naturally imposes certain restrictions. To what extent exceptions are possible is still beyond my construction-related knowledge — if they are necessary at all.
Some key data: floor area ratio 0.4; floor space index 0.5; one full story; roof pitch 25-35 degrees Celsius (77-95 Fahrenheit); gable and hip roofs permitted; building height 3.50 meters (11.5 feet), measured from the ground floor finish level to the top of the rafter at the outer wall at roof section.
The plot is trapezoidal, approximately 30 by 20 meters (100 by 65 feet). I can prepare a sketch if needed.
I would basically build on my own, which financially should not be a problem given my income. An initial consultation with a mortgage advisor based on my first, naively estimated budget of around €500,000 (about $545,000) did not raise any major concerns, especially since I have significant equity and the plot is quite expensive, which obviously increases the overall value.
What is to be built:
- Two separate residential units — it’s still open whether they will be divided between ground floor and upper floor or via a granny flat / secondary unit
- About 200 square meters (2,150 square feet) of total living space, with approximately 120/80 square meters (1,300/860 square feet) planned — based on my initial research, this size might make a secondary unit somewhat complicated. Basically, 70 square meters (750 square feet) would also be sufficient, but it should not fall below that
- Either a basement or a larger living area for the bigger unit — this might sound odd, but I don’t particularly care where I can have some extra space for a small gym, hobby room, etc.
- I am indifferent about the construction method — it doesn’t have to last forever but should offer a high standard of sound insulation, especially between the two units. The surroundings are far from noisy, but I always expect the worst-case scenario
- Double garage for the first construction phase; two carport spaces planned for the second phase, but not realized immediately
- Exterior landscaping will be done by myself; the residential unit delivered turnkey
The basic idea is to completely finish the larger unit to make it immediately habitable, while the smaller unit will be kept in reserve. I am not sure to what extent finishing is necessary there to maintain the building fabric. There definitely won’t be a bathroom, except for any required connections.
Of course, I have looked for inspiration among the usual prefab house providers for possible realizations. I am not sure how welcome direct references or links are here.
My question: with these key data, do I already have a fundamental planning mistake at this stage? Is a budget of about €450,000 (roughly $490,000) plus 10% contingency (for the first construction phase only) totally unrealistic? I have of course browsed through this forum seeing price per square meter figures, but I have no idea how these two construction phases would influence the costs. I understand costs vary drastically depending on fittings and finishes — but hopefully, during planning, one can get closer to more reliable values.
My approach now would be, after your plausibility check, to find a possible floor plan in the prefab house sector and based on that evaluate other building types or discuss further with the prefab house provider.
Thanks in advance 🙂
One hundred twenty square meters plus a gym and a double garage for you, and seventy square meters reserved for whom and when?
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
EineEULE schrieb:
Building height 3.50m (11.5 feet) measured from ground floor level to the top plate/ridge intersection of the exterior wall and roof section Basically the eaves? So the exterior envelope of the wall?
EineEULE schrieb:
Roof pitch 25–35 degrees; EineEULE schrieb:
120/80 sqm (1292/861 sq ft) At 35 degrees, there isn’t much usable living space upstairs. With a 70cm (28 inch) knee wall, a 20-meter (66 feet) wide house offers roughly 8 meters (26 feet) of living width upstairs. That’s enough for a workout room.
With a 10-meter (33 feet) wide house and the same 70cm (28 inch) knee wall, there is only about 3 meters (10 feet) of usable width at the top...
@11ant: Valid question. The house will be located near the city, on the outskirts of Stuttgart (in the broader sense). My parents currently live in a relatively large house in the countryside, and it is foreseeable that they will move into this apartment in about 15 years (barrier-free, local infrastructure, etc.).
Regarding space requirements, I have tentatively planned for a two-person household in the larger apartment, which for me means two rooms per person for "free" use, such as an office. I have already been working from home quite a lot and will work from there at least three days a week, so I value physical separation and a quiet working environment. If I now factor in two potential children's rooms, there is not much space left for "extras" like a fitness area. I understand that one of the major mistakes in capital investment is creating excessive room in anticipation. I am trying to keep this as minimal as possible, but my current 2.5-room new-build apartment with just under 65sqm (700 sqft) already shows me the limits of too little space despite a good floor plan...
@ypg: Thank you very much! This is exactly the topic where I currently lack a spatial understanding or a practical sense of what these parameters mean. Of course, I understand the terms—but only by definition. The wording is also not entirely clear to me and comes directly from the development plan. Without fully understanding the detailed impact, I had already anticipated that this might be the first area I need to address. Three development plans intersect at my building plot, and about 150 meters (500 feet) away there is a fourth development plan. This means that the next plot to the south is developed with 2.5 stories, the other two sides with my development plan and a former agricultural operation (house with two full stories). In the line of sight (150 meters (500 feet) from me), cube-shaped houses with flat roofs and three full stories have already been built.
I do not intend to build a high-rise there, but currently a hipped roof with two full stories is my favorite option. Does it make sense to get legal advice on building regulations here? Are the directly adjacent 2.5-story buildings an advantage (other than that they are on my south side)? One of the houses was extended nearly 15 years ago—but that falls under the other development plan. By the way, according to the plan, my building plot falls within the village area (historically part of the agricultural operation), while the others are designated as general residential areas.
Regarding space requirements, I have tentatively planned for a two-person household in the larger apartment, which for me means two rooms per person for "free" use, such as an office. I have already been working from home quite a lot and will work from there at least three days a week, so I value physical separation and a quiet working environment. If I now factor in two potential children's rooms, there is not much space left for "extras" like a fitness area. I understand that one of the major mistakes in capital investment is creating excessive room in anticipation. I am trying to keep this as minimal as possible, but my current 2.5-room new-build apartment with just under 65sqm (700 sqft) already shows me the limits of too little space despite a good floor plan...
@ypg: Thank you very much! This is exactly the topic where I currently lack a spatial understanding or a practical sense of what these parameters mean. Of course, I understand the terms—but only by definition. The wording is also not entirely clear to me and comes directly from the development plan. Without fully understanding the detailed impact, I had already anticipated that this might be the first area I need to address. Three development plans intersect at my building plot, and about 150 meters (500 feet) away there is a fourth development plan. This means that the next plot to the south is developed with 2.5 stories, the other two sides with my development plan and a former agricultural operation (house with two full stories). In the line of sight (150 meters (500 feet) from me), cube-shaped houses with flat roofs and three full stories have already been built.
I do not intend to build a high-rise there, but currently a hipped roof with two full stories is my favorite option. Does it make sense to get legal advice on building regulations here? Are the directly adjacent 2.5-story buildings an advantage (other than that they are on my south side)? One of the houses was extended nearly 15 years ago—but that falls under the other development plan. By the way, according to the plan, my building plot falls within the village area (historically part of the agricultural operation), while the others are designated as general residential areas.
Before you start thinking about the appearance of the house, it would be sensible to design the room layout first. The small apartment should be designed to be barrier-reduced (fully accessible is very precisely defined, quite challenging for a single-family house, and focuses on the effortless use with a wheelchair). This would mean that the apartment would ideally be on the ground floor. Here it gets interesting: do you really want to leave about 80m² (860 sq ft) unfinished on the ground floor with garden access, etc., vacant for 15 years?
The large apartment could then be divided between the ground floor and the upper floor. Probably with an open-plan kitchen/living area on the ground floor (garden access) and living rooms, hobby rooms, etc., upstairs. And again the question arises – am I willing to limit my use for 15 years? Or would I even like having the living area on a different level than the “guest area” (kitchen, dining, terrace)? After all, there are also people who love maisonette apartments.
Once you have thought through the room concept for yourself, you can then look at how it can be realized within which building envelope and what type of house fits this as well as the zoning plan (with possible exceptions).
The large apartment could then be divided between the ground floor and the upper floor. Probably with an open-plan kitchen/living area on the ground floor (garden access) and living rooms, hobby rooms, etc., upstairs. And again the question arises – am I willing to limit my use for 15 years? Or would I even like having the living area on a different level than the “guest area” (kitchen, dining, terrace)? After all, there are also people who love maisonette apartments.
Once you have thought through the room concept for yourself, you can then look at how it can be realized within which building envelope and what type of house fits this as well as the zoning plan (with possible exceptions).
That is completely justified as well. In principle, you have anticipated the desired layout, but I see the issue with the size of the granny flat only on the ground floor as critical. This will probably be the first area to be reduced in order to make the floor plan fit, but I do not want a simple 2-room apartment as the granny flat. Some living quality should also be provided there.
I am well aware that having a vacancy is far from ideal. However, I also need to do something about the existing building plot ;-)
My current favorite plan has apartment 1 on the ground floor with a utility room, guest toilet, kitchen, and living/dining area, and the remaining rooms on the first floor. Apartment 2 on the ground floor has its own laundry/utility room and two well-laid-out rooms around the corner. It is important to me that storage options or a utility room are also available for the second apartment. My parents think that 50 sqm (540 sq ft) would be sufficient for them; I have a slightly different opinion, but I think we can reach a compromise, especially since I am the cautious one here. As my father will soon have trouble with stairs, the ground floor is the only reasonable option—and then, at the latest, that will be the time when the current house must be replaced.
Am I allowed to link prefabricated houses or post the floor plans here? Anyone interested can search for Massa Haus FamilyStyle 20.02 W. I am only interested in the exemplary layout—regardless of details or conflicts with the building permit / planning permission.
I am generally quite rational and approach building unemotionally, as you might have noticed. Of course, I have my ideas, but overall I am realistic. Compromises are part of life.
I am well aware that having a vacancy is far from ideal. However, I also need to do something about the existing building plot ;-)
My current favorite plan has apartment 1 on the ground floor with a utility room, guest toilet, kitchen, and living/dining area, and the remaining rooms on the first floor. Apartment 2 on the ground floor has its own laundry/utility room and two well-laid-out rooms around the corner. It is important to me that storage options or a utility room are also available for the second apartment. My parents think that 50 sqm (540 sq ft) would be sufficient for them; I have a slightly different opinion, but I think we can reach a compromise, especially since I am the cautious one here. As my father will soon have trouble with stairs, the ground floor is the only reasonable option—and then, at the latest, that will be the time when the current house must be replaced.
Am I allowed to link prefabricated houses or post the floor plans here? Anyone interested can search for Massa Haus FamilyStyle 20.02 W. I am only interested in the exemplary layout—regardless of details or conflicts with the building permit / planning permission.
I am generally quite rational and approach building unemotionally, as you might have noticed. Of course, I have my ideas, but overall I am realistic. Compromises are part of life.
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