Bricking up the garage. Tips?

As if I had smelled it coming.

Basement replacement room is not the same as a garage.

And presumably, only a garage is permitted there.

If everything is to be done properly, you have to get permission for the change of use. And whether your building can be approved there, I cannot judge.

And yes, the building authority visited me three times unannounced during the construction phase of about 9 months.

According to the State Building Code of Schleswig-Holstein, both a garage and, among others, other buildings without living spaces are permitted on the property boundary. So that is not a problem.
Furthermore, the State Building Code states: "Garages are buildings or parts of buildings for parking motor vehicles." From my point of view, this means that if I simply use the "garage" to park my motor scooter, it is already a garage according to the definition. However, I will ask about that again in detail.

I think it has now happened. The gate is gone. But I would have left it in. And simply not parked the car in there. My garage will never house a car either, it’s a cheap workshop, garden shed, etc. And as long as a gate is there, it is a garage. And as long as our car is not parked on the street, nobody will care. Whether the lawn mower or the VW is inside is all the same to the neighbor...

We removed the garage door because, firstly, it was defective, and secondly, because contrary to the previous development, now only a footpath and no driveway lead past there. A garage door would therefore not be visually appropriate. Moreover, it takes up parking space inside.

What do you expect? - not seriously that they recommend a different material, right?

How does one even come up with the idea of cutting a garage in length "with basement replacement" to "if basement replacement, then only long enough for a second car," and then also want to replace the door maintaining the appearance of a garage? - I would at least reinstall the door and make my first masonry attempts with a garden grill. Not everyone has one made of calcium silicate.

Then the garage would just be shortened like a pair of pants and all peace restored. No building authority will complain about a few wine bottles in the garage. And with a door, you can carry out bulky waste much more comfortably.

No, I don’t expect that. On the one hand, they are supposed to inform me about the load-bearing capacity of the ceiling beams; on the other hand, you can hear their suggestions for the new wall.

I feel like I’ve received 15 different tips from 10 different users now. On MyHammer I got one offer in a week to build the wall for almost €2,700 (without materials)...
I will probably try it myself anyway. You can always remove it.

On the one hand, you want to enlighten me about the load-bearing capacity of the ceiling beams,

This precast ceiling holds, as you can see, self-supporting – and, as you probably also see, with minimal deflection. The reinforcement is likely the same for middle elements as for end elements of the same span. Therefore, it should not make a difference to the current front end element to have previously been a middle element. In other words: not "load-bearing" statically for what is underneath. Nevertheless, I would build with 24 cm thickness. Masonry is, by the way, a serious vocational training profession – you will see in practice that it's not as easy as playing in the sandbox. You will be amazed at how a 12 mm mortar joint is enough to make the wall crooked. Perhaps, as a hobby mason, you’d better use aerated concrete plan blocks and save the beautiful sand-lime bricks for the grill.

Thanks again for all your opinions and answers! I have now found a bricklayer who will at least provide me with assistance.

What is your view on the frost protection strip? Does it necessarily have to be relocated under the new wall? And if so, is that solely for protection against frost and moisture or also for stability reasons? At the moment, there is about 20 cm thick reinforced concrete at the spot where the new wall is supposed to go.

Best regards

At the moment, at the spot where the new wall is supposed to go, there is about 20 cm thick reinforced concrete.

Even a foundation does not replace that. You don't shorten a garage as easily as a pair of pants (or you also have to sew the hem again with the garage).