The houses are intended to serve as a capital investment (pension). In our area, there are no houses in the price range of 1200-1500€ (cold rent).
Okay, then a semi-detached house.
You are right, there are plenty of catalog models, the problem is that almost all of them face south or exceed the width of 15m.
Still resort to catalog models. As you describe the market, there would be excess demand to build semi-detached houses (which developers also offer), but for rent (they don’t offer that, and that would be your market niche). So find a template for a semi-detached house (and on the one hand use the freedom of the undivided plot and on the other hand spread your risk by making the halves unequal for only similar but not identical target groups; i.e. think away from the 50/50 width division). Build a semi-detached house, e.g. 7m/8m wide, and already look for rental applicants during the planning phase, to whom you still offer some influence – basically like a developer, only renting out. Of course only to a limited extent (no full floor plan discussion with the first occupants, only a max. of two non-load-bearing walls may be moved, choice of floor coverings etc.). I also always advise the standard gradation (in the 8m half a “masonry” walk-in shower, in the other only a glass cabin, double washbasin added in the major house and classic basin in the minor house, etc.), but strictly speaking I consider the batch size of 2 housing units as an investor project peanuts, just to mention this for the sake of order. I see no point in a floor plan discussion
with you, you don’t want to build
for own use. Investment properties should be approached unemotionally and market-oriented. You have already taken the first step “market oriented” by probing the market and justifying the semi-detached house. Now you should refine this (see my suggestion with the standard differentiation and thus securing the first occupants) and also take the second step, not to make the floor plan
your baby.
Is there one heating system for all houses together?
I find a common heating system / or a shared connection room for both units good – but how does come up with a six-family house???