ᐅ Duplex as a single residential unit or two "half-houses" – What should be considered?

Hello,

As part of the preliminary planning for developing a plot of land with possibly a semi-detached house as an investment, both units are initially intended for rental. One unit might be used personally later on (in 15-20 years).

I am considering whether to build them as fully separate units or as a multi-family house (WEH). Especially since I have also seen hybrid solutions offered by prefab house manufacturers. I would appreciate your opinions on my considerations...

Separate semi-detached house:
- Easier to sell individually after possible subdivision of the plot
- Better sound insulation between the two homes
- Separate technical systems for each house → redundancy and clear cost allocation
- Easier sale of "one half" in case of emergency (really?)

Multi-family house (WEH):
- Only one technical system needed (probably cheaper)
- Slightly smaller space requirement for the dividing wall
- More options for asymmetrical layouts

What do you think about these points? Are there any additional aspects to consider?

Thank you very much

First of all, it’s WEG, not WEH, but whatever.

If it is legally allowed under building regulations, I would recommend a real division. Especially with a semi-detached house, WEG division can be rather problematic and may discourage potential buyers.

I don’t understand what influence this should have on the party wall. (Sound insulation, space requirements)

With a single heating system, you still need billing and distribution, so more meters, meter replacement, and annual readings with billing. What an effort—time is money. And if the heating breaks down, the entire house gets cold... which is also less than ideal for rental purposes.

Asymmetry tends to make construction more expensive. Building expensively for rental? And I wouldn’t overestimate owner occupancy in 20 years either.

How can a newly built semi-detached house be financially viable through rental income at current construction costs?

I mean, if someone is willing to pay around 1500€ (about 1600 USD) monthly rent excluding utilities to live in a house, they would probably go to the bank, get a suitable loan, and build according to their own preferences. In other words, the people moving into your property will likely be
A) those who cannot get a loan. But how can you be sure that these people will consistently be able to afford such high rent? There’s a reason why the bank said NO to them.
B) tenants who want flexibility – which is also a problem from a landlord’s perspective, especially in a newly built house, where frequent tenant turnover quickly wears down the high standard, leading to additional maintenance and repair costs.

Later owner-occupation is also complicated. Consider, for example, a retired couple who suddenly develop limited mobility or a young family with a seriously ill child moving in… you will almost never be able to evict such tenants in these difficult situations.

What do the state building codes or zoning plans say? Some plots of land cannot be legally subdivided due to their size.

RomeoZwo schrieb:
Both halves are to be rented out first, with one half possibly used as owner-occupied later (in 15-20 years).

Building a house 15 to 20 years before you plan to live in it yourself – so long before you start saving on rent elsewhere – strikes me as economically very questionable. Even with careful use, you no longer have a new house after that time.

In my opinion, building wealth as a landlord with this model only works if you build the same property three, four, or five times.

For a duplex, I don’t see what makes a vertical layout significantly more attractive than the classic stacked design with one dwelling unit per floor.

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The apartment needs to be properly repaired again, at least according to some tenants 😉