Two-family house new construction - Which costs to calculate?

How do you come to the conclusion that the OP is about 3 residential units?

The OP mentioned an apartment with a separate entrance in some posts: parents' apartment + OP + separate apartment = 3 residential units.

Or he meant the separate apartment as the apartment for the parents. Then, of course, only 2 residential units. Maybe sooner or later he will consider that he gets more space in the attic than he actually needs or arranges the rooms in such a way that a self-contained apartment is created. Then just the note that dealing with 3 residential units is entering completely new territory.

Good evening,

the OP is not sure whether it is a granny flat or simply an apartment on the ground floor.

What I would be interested in, however, is what makes you so sure that you can change the development plan for your property to 3 residential units by exemption?

Rhenish greetings from the road
Building expert

Just to clarify again: I need 2 residential units. I just can't decide whether a house with a granny flat or a house with two complete apartments. Although I still can't see a clear distinction. What are the differences?

The idea of a multi-generational house where part of the larger apartment is on the ground floor I currently find really great, as you can implement many things the way I imagine.

The problem is simply that I have no idea about the price,

Please always assume 2 separate residential units. That means separate entrances, separate sanitary facilities, and very importantly, two separate financings for the residential units. This way you can also use Wohnriester to repay the loans for your own residential unit. From a tax law perspective, it should also be handled separately, as you can then claim the interest for the rented residential unit.

I am not renting out the second residential unit (at least as long as my parents are alive) - they enjoy a lifelong right of residence there.

You will have to explain to me how I am supposed to finance separately when building a new property. Then only the interior construction, right? But if I commission an architect to build a house with 2 residential units, he wouldn’t create two separate invoices, nor have the craftsmen create them, would he?

I am completely inexperienced in this area. I have only heard of Riester vaguely.

Rent would be tax-deductible (if eventually my parents no longer live there), and I can also claim the loan interest - that much is clear. This should generally have a positive effect on my finances, otherwise no one would rent out apartments. But as I said, renting out is not happening for now anyway. And simulating a rental, that is, drawing up a lease agreement to enjoy these tax benefits without ever actually paying the agreed amount, would in my opinion be tax fraud, right?

I understood it as being possible to do it based on the floor area. That means, for example, I take out two loans. One for the 70sqm and one for the 150sqm. Then you can service the loan for the large residential unit with Riester at any time, since it is owner-occupied residential property. And yes, receiving fictitious rent is tax fraud, but some people have a rather flexible conscience about that.