Hello,
My partner and I are planning to build a duplex together with a couple of friends.
The two living units are not stacked on top of each other but are arranged side by side in two equally sized sections, each with its own entrance door. From the outside, it looks like a semi-detached house with mirrored halves. Each half spans two full floors plus a converted attic. Inside the house, there is a shared utility room, which is proportionally deducted from each living area and accessible from both sides through a door.
There is a single heat pump serving both halves.
I’m interested to know if anyone has experience with a similar project. We have several questions regarding the partition plan, deed of division, and condominium declaration.
In order for each household to secure its own financing, these matters need to be clarified beforehand. From what I understand, the architect must submit the partition plan at the same time as the building permit / planning permission application, but I might be mistaken?
We are also concerned about separating the heating and water systems so that each party can be billed accurately for their individual consumption.
I would appreciate any experiences or advice on these topics.
My partner and I are planning to build a duplex together with a couple of friends.
The two living units are not stacked on top of each other but are arranged side by side in two equally sized sections, each with its own entrance door. From the outside, it looks like a semi-detached house with mirrored halves. Each half spans two full floors plus a converted attic. Inside the house, there is a shared utility room, which is proportionally deducted from each living area and accessible from both sides through a door.
There is a single heat pump serving both halves.
I’m interested to know if anyone has experience with a similar project. We have several questions regarding the partition plan, deed of division, and condominium declaration.
In order for each household to secure its own financing, these matters need to be clarified beforehand. From what I understand, the architect must submit the partition plan at the same time as the building permit / planning permission application, but I might be mistaken?
We are also concerned about separating the heating and water systems so that each party can be billed accurately for their individual consumption.
I would appreciate any experiences or advice on these topics.
[QUOTE="11ant, post: 681982, member: 32750"]
I’m not sure if or when @i_b_n_a_n will accept my invitation to contribute here. However, that doesn’t mean the meantime should be “used” to throw a handful of basic framework facts together with various mistaken assumptions into a cocktail shaker. Let’s stick to the facts:
So, two couples (with still uncertain but parallel family planning) and a plot of land that, even after subdivision, would not allow the construction of a semi-detached house. That is a fact and requires a purely theoretical subdivision (recommended as a condominium ownership / strata title) as a two-party house. Combined with separate financing, the legal form of a condominium ownership / strata title is a further factual requirement. The ownership shares do not need their own land area; they could be realized not only as a (not necessarily symmetrical!) semi-detached house but also as a classic two-family home with separate floors (e.g., with a utility room in the attic). At this point, I’d like to suggest, at least hypothetically, putting the friendship to the test with a bunk bed scenario: who would yield to the other on the coin toss, who "sleeps upstairs"?
That both dwelling units could share what I might call a “common combined heat and power unit” is also an economic fact and quite reasonable, which is why it will remain that way. Behind this, individual meters can be installed for both parties, just like in a conventional multi-family house. Keeping a second blind utility room in reserve for separating the community seems excessive to me. How the shared technical center is operated can, in principle, be decided by the owners’ meeting. To avoid a deadlock, I recommend allocating voting rights according to exclusive use areas. Practically, this could be done most easily by arranging (whether as a semi-detached house or a classic two-family home) the utility room (if mainly located in the attic, then the house entry room) so that the ownership share closer to it effectively becomes smaller. For example, utility room in attic 10 sqm (108 sq ft), house entry room on ground floor 3 sqm (32 sq ft), apartment A 97 sqm (1044 sq ft) and apartment B 100 sqm (1076 sq ft), shared garden use, meaning co-owner B would decide in a dispute with 100/197 voting shares. Is the friendship still intact at this point?
As long as the separation of units is maintained (each unit requires a cooking facility and a toilet), the rest of a house can be completely filled with utility and connection rooms. Several meters can be connected downstream to hot water tanks. And I have yet to hear of a single case in countless six-family buildings divided into condominiums where a four-sixths co-owner told the others to get their own boilers and canceled their access to the shared heating supply. The residual risk of a lunar eclipse on Saint Never-Day can hardly be eliminated. So, besides belt and suspenders, adding insurance for hypochondria—one can always overdo it.
In theory or as a condominium ownership / strata title, no development plan limits the number of entrance doors. Presumably, two residential units per plot are allowed here, and it should be avoided that four units (equivalent to 6 or 8 parking spaces) arise on the property.
So: talk to each other, do the bunk bed test. Depending on the outcome, follow my inclination to build a classic two-family house here or choose an “ideal semi-detached house.” Either way, either follow my warning about deadlock (there’s probably little way around a condominium ownership / strata title for financing purposes here) by creating a slight asymmetry in voting shares (in my model, the same party that "gives up" the area for the shared utility room must also endure being overruled), or provide redundancy by reserving a potential second utility room. You’ll have to suffer one way or another—washing without getting wet doesn’t work.
Currently, the house connection room / utility room is arranged so that each party requires 6 sqm (65 sq ft) of floor area on the ground floor. In principle, the dividing wall between the two units could simply run through the utility room, giving each their own. Only the house connections would then be located either on the left or right side.
I’m not sure if or when @i_b_n_a_n will accept my invitation to contribute here. However, that doesn’t mean the meantime should be “used” to throw a handful of basic framework facts together with various mistaken assumptions into a cocktail shaker. Let’s stick to the facts:
So, two couples (with still uncertain but parallel family planning) and a plot of land that, even after subdivision, would not allow the construction of a semi-detached house. That is a fact and requires a purely theoretical subdivision (recommended as a condominium ownership / strata title) as a two-party house. Combined with separate financing, the legal form of a condominium ownership / strata title is a further factual requirement. The ownership shares do not need their own land area; they could be realized not only as a (not necessarily symmetrical!) semi-detached house but also as a classic two-family home with separate floors (e.g., with a utility room in the attic). At this point, I’d like to suggest, at least hypothetically, putting the friendship to the test with a bunk bed scenario: who would yield to the other on the coin toss, who "sleeps upstairs"?
That both dwelling units could share what I might call a “common combined heat and power unit” is also an economic fact and quite reasonable, which is why it will remain that way. Behind this, individual meters can be installed for both parties, just like in a conventional multi-family house. Keeping a second blind utility room in reserve for separating the community seems excessive to me. How the shared technical center is operated can, in principle, be decided by the owners’ meeting. To avoid a deadlock, I recommend allocating voting rights according to exclusive use areas. Practically, this could be done most easily by arranging (whether as a semi-detached house or a classic two-family home) the utility room (if mainly located in the attic, then the house entry room) so that the ownership share closer to it effectively becomes smaller. For example, utility room in attic 10 sqm (108 sq ft), house entry room on ground floor 3 sqm (32 sq ft), apartment A 97 sqm (1044 sq ft) and apartment B 100 sqm (1076 sq ft), shared garden use, meaning co-owner B would decide in a dispute with 100/197 voting shares. Is the friendship still intact at this point?
As long as the separation of units is maintained (each unit requires a cooking facility and a toilet), the rest of a house can be completely filled with utility and connection rooms. Several meters can be connected downstream to hot water tanks. And I have yet to hear of a single case in countless six-family buildings divided into condominiums where a four-sixths co-owner told the others to get their own boilers and canceled their access to the shared heating supply. The residual risk of a lunar eclipse on Saint Never-Day can hardly be eliminated. So, besides belt and suspenders, adding insurance for hypochondria—one can always overdo it.
In theory or as a condominium ownership / strata title, no development plan limits the number of entrance doors. Presumably, two residential units per plot are allowed here, and it should be avoided that four units (equivalent to 6 or 8 parking spaces) arise on the property.
So: talk to each other, do the bunk bed test. Depending on the outcome, follow my inclination to build a classic two-family house here or choose an “ideal semi-detached house.” Either way, either follow my warning about deadlock (there’s probably little way around a condominium ownership / strata title for financing purposes here) by creating a slight asymmetry in voting shares (in my model, the same party that "gives up" the area for the shared utility room must also endure being overruled), or provide redundancy by reserving a potential second utility room. You’ll have to suffer one way or another—washing without getting wet doesn’t work.
Currently, the house connection room / utility room is arranged so that each party requires 6 sqm (65 sq ft) of floor area on the ground floor. In principle, the dividing wall between the two units could simply run through the utility room, giving each their own. Only the house connections would then be located either on the left or right side.
S
Singelküche3 Feb 2025 18:42I have built something like this almost 30 years ago.
The property has only one driveway. It looks like a semi-detached house but actually consists of two separate flats. Each flat had a secondary entrance door, and both shared only one main entrance door with a small hallway leading to the flats.
The architect explained to me that it would not have been possible to get approval any other way. At that time, the trend with geothermal energy and so on hadn’t started yet.
Each flat has its own utility connections, and they are sold on the real estate market just like a semi-detached house. Without any compromises or higher interest rates. Today, I would probably try a solution like Waldrich’s, with just one utility room or boiler room. Reading sub-meters is not a big project. Easements for pipes over other properties might also need to be considered.
The property has only one driveway. It looks like a semi-detached house but actually consists of two separate flats. Each flat had a secondary entrance door, and both shared only one main entrance door with a small hallway leading to the flats.
The architect explained to me that it would not have been possible to get approval any other way. At that time, the trend with geothermal energy and so on hadn’t started yet.
Each flat has its own utility connections, and they are sold on the real estate market just like a semi-detached house. Without any compromises or higher interest rates. Today, I would probably try a solution like Waldrich’s, with just one utility room or boiler room. Reading sub-meters is not a big project. Easements for pipes over other properties might also need to be considered.
Teimo1988 schrieb:
I have done something pretty much like what you are planning, or rather I am currently finishing the construction phase of the project.(Where) have we discussed this here before? Waldrich schrieb:
Currently, the utility room/house connection room is designed so that each unit requires 6 sqm (65 sq ft) of floor space on the ground floor. In principle, you could place the dividing wall between the two units through the utility room, so that each would have their own.
Only the utility connections would then of course be located either on the left or right side.Oh, there is already a plan? (I don’t recall) – please share it here.https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
N
nordanney3 Feb 2025 19:01Waldrich schrieb:
Currently, the utility room/house connection room is arranged in such a way that it requires 6 sqm (65 sq ft) of floor space from each party on the ground floor. May I ask what you plan to do with the extra space then? In the end, there is hardly anything stored there, and you have 4 sqm (43 sq ft) set aside as a guest room.
With that size, I can't think of any reason not to divide it into two separate rooms.
Waldrich schrieb:
I had the same thought—apart from the additional costs (even if it means two smaller heat pumps instead of one large one), each half would of course need to have a sufficiently sized utility room, which naturally reduces the living area.I read this earlier as if you were planning only one technical room for two households to save on non-living space.Waldrich schrieb:
Currently, the house connection room/utility room is arranged so that it uses about 6sqm (65 sq ft) of floor space for each party on the ground floor. Basically, you could place the dividing wall between the two units through the utility room, so that each would have its own.
Only the house connections would then, of course, be located either on the left or right side.So, instead, you’ve already planned a 12sqm (130 sq ft) technical room, centered along an unbuilt partition line, with the required equipment on one side of the floor plan half and the other side serving as shared storage space?https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
T
Teimo19883 Feb 2025 20:0711ant schrieb:
(Where) have we discussed this before?The planning was (unfortunately?) never presented here. I only really discovered the forum after the planning phase and during the construction. However, I’m happy to share the whole process if anyone is interested or if it might be helpful to someone.Similar topics