Garage Partially Basement KF40 Compliant

We got a plot of land; the area is a new housing development. The house should be about 140-160 sqm in size. The house will be built solid.

How would you handle the granny flat?

Honestly, that depends on what you can afford, whether there is a target group for external tenants in the new development area, how it would be taxed, and what the bottom line ultimately is. Whether it works out well with your financing.
50 sqm rented out to an older tenant is probably off the table because of the idea of an attic conversion; younger individuals usually mean turnover and possibly vacancy for a few months, but repeatedly.

It also depends on your plot: 515 sqm, we don’t know the development plan. Are you allowed to build a granny flat? How many parking spaces per housing unit are required for you? With two housing units, that could mean up to 4 parking spaces. With 515 sqm that’s already more than tight. Possibly the building area isn’t sufficient at all, possibly you’re only allowed to build up to a certain maximum height.
You have to look at what the floor area ratio and the plot ratio allow. You can’t just realize whatever you have in your head, that often doesn’t work.
You would have to upload the site plan and the development plan here once so that it can be checked whether there is legal capacity at all and what kind of house fits on it. And not to forget: then you design around a granny flat, everything (house and life) somehow becomes a compromise and mom will show you the bird in 10 years because she marries overseas.

We do a lot ourselves, since we have a very large family.

DIY work is probably not allowed at all if you want something from the KfW40 program? Or does that only apply to QNG (or whatever it’s called)?

Big thanks to you already!

My mother brought up the idea once. But it is not absolutely necessary. We thought that if it's a [Einliegerwohnung], then the storage room and toilet should face the garden.

Is the KFW loan still worth it?

KfW 300 is still worth it. 124 is not, 297 only a little.

The property itself is also important, which is still unknown. In addition, there are different types. For example, Type 1 may only be built as a single storey. May I ask if you have ever dealt with your property at all? I mean, have you read all the fine print, drawn the plan, calculated the floor area ratio, etc.? It makes no sense if we deal with it and you do not.

Thank you, but links are deleted here. The property itself is important, which is still unknown. In addition, there are different types. Type 1, for example, may only be built as a single story. May I ask if you have ever dealt with your property at all? I mean, have you read all the fine print, drawn the plan, calculated the floor area ratio, etc.? It makes no sense if we deal with it and you don't. .

So only gable roofs are allowed. You are allowed to add one residential unit. We must stay 3m away from the property boundary. The garage can start at 6m but can be built on the boundary. You are allowed to build up to 3 stories.