Monument protection, also for a stable or only a residential house?

Hi,
I looked at a half-timbered house from 1800. Directly attached to the residential building is a stable building. I would like to use this stable building for animal husbandry. For that, it would be good if I could tear down a wall or at least enlarge the windows.

I would then have to submit an application to the heritage protection authority, right?

Does anyone have experience with how good/bad my chances are for my project?

Oh, one more thing I forgot:

The roof of the house also needs to be renewed soon. Since the house is mainly heated with electricity, I would like to put solar panels on the roof. Do you also need permission for that because of [Denkmalschutz]?

Best regards

Good evening,

feed Aunt Google with "Denkmalschutz Niedersachsen" - there is, among other things, a pdf from the Niedersächsisches Landesamt für Denkmalschutz available for download

Rhenish greetings

First, find out whether the house is listed as a historic monument. Old does not automatically mean [Denkmalschutz].

I know that the house is a listed building, including the parts of the stable that are inside the building. I am interested in the part of the stable that was attached to the house.