500-year-old Jura marble floor... what to do with it?

If you like a [Landhaus küche], then install it there.

It won't be a country-style kitchen... The new build will be more of a modern thing, we would really like to actually install it somewhere, I’m just still dreading the extra effort... I hate fighting with myself....

What do you mean by much more that could be good?

Primarily, I meant that I expect more intact pieces than you want to reuse yourself. I think you will use it as an accent in the living area and/or entrance area, but not as a continuous covering throughout the whole house. But ...

Do you mean other things besides the tiles?

... of course, that would also be a charming idea.

And how can you make a profit from that?

By other people being totally crazy about something that may seem normal to you. For you, they are familiar traditional floor tiles; for Japanese people in Düsseldorf, they might be willing to pay kilo prices you wouldn’t have expected for the quintal.

I'm just still dreading the extra effort...

It will be worth it.

I hate fighting with myself....

Oh well. If you're half as strong as your avatar, then you win ;-)

Suppose I decide to tile the entrance area with it, how do you manage that? Then the screed must be lower up to the edge where it continues with parquet. Is that even possible properly with built-in underfloor heating? And actually, we also wanted a recessed foot scraper mat from Aco in the tile bed in the entrance area.....

Except for the marble floor, if anything, only the oak beams from the entire timber frame would be of interest, but rather for furniture making. It was already crazy how many carpenters called us when it became known that this Jurahaus was going to be demolished.... Otherwise, the house only contains clay, straw, brick, and the Legschiefer roof.

Assuming these are for example about 1.5 to 2 cm thickness difference. I would, if necessary, already take that into account in the floor slab / cellar ceiling, and make this area correspondingly thinner. At the transition, you do this into the other area and blend it diagonally. The "slope" at the transition will allow the underfloor heating to cope. The harder way would be to have the screed layer in this area inoculated by an ambitious terrazzo manufacturer, thinking a bit more complex.

Otherwise, in the house there is only clay, straw, brick, and the slate roof.

The roof also sounds interesting. Brick, yes, at first glance banal. But building your own wine cellar is currently quite "in". Every fool is different ...