Floor plan conversion of part of a barn into a single-family house with the option for a two-family house

Are you talking about this one?

https://www.hausbau-forum.de/threads/mehrgenerationenhaus-baut-alte-scheune-um-200m2-auf-3-5-ha-grund.38055/

In my opinion, up to service phase 4 the architect is almost always the better solution. Especially since the mentioned architect is supposed to have experience with such conversions. For the conversion of the barn, you probably won't find a contractor who can cover the rest well.

All right, so we will first get in touch with our architect again and wait to see what she suggests. It seems that this is the consensus here, so we will do that. Thanks for the tip!
By the way, we will build without a contractor and do most of it ourselves. We are not under any time pressure concerning the construction, the necessary equipment is available, there are people from relevant trades in our immediate family, and my boyfriend and his family have already built his parents' house themselves.

I am curious to see the pictures of the interior. If the roof structure [Dachstuhl] can be preserved, a lot of money will be saved.

I would like to accept some technical arguments.

I didn't mean to say that one should just quickly put three lines on paper. But the floor plan with given exterior dimensions should not have priority, rather the question "Can I convert the barn". There is that saying about the bear and its fur ;-)

This is somewhat related to the fact that, according to our architect, we first have to bring the barn partly to the condition of "worth preserving building fabric," since we probably wouldn't get approval in its current state. So some parts of the barn need to be renovated first (which is possible without a building permit) and then re-zoned. For example, this concerns the northern wall, which consists of half-timbering that must be completely renewed. However, to avoid unnecessarily putting obstacles in the way of the later conversion during this renovation (e.g., regarding the division of the half-timbering), we would first like to work out a rough idea of our later floor plan. This requires a delicate approach, of course coordinated with the architect...

Hello! We have a similar project, and depending on the region, re-zoning is indeed rarely a problem as long as you are not converting a solitary barn in the open countryside. But I can also strongly recommend first hiring a structural engineer—or an architect very familiar with structural engineering in special buildings—to assess the structural conditions of the building; half-timbering rarely can be significantly altered in its existing condition. Unless you open up a really big can of worms and completely rebuild the roof with ring beams and all the bells and whistles. The same applies to the supports. And if you have to watch your budget—save yourself the hassle of trying to fit a floor plan for potential rentals together with your living wishes under one roof right now. Nobody knows what will happen in 10 or 20 years. And renting also means, depending on the building regulations, additional requirements regarding fire safety, escape routes, etc. That will certainly not decrease. I would only open that can of worms when the situation occurs.

Do you mean this one?
https://www.hausbau-forum.de/threads/mehrgenerationenhaus-baut-alte-scheune-um-200m2-auf-3-5-ha-grund.38055/
But that's a completely different magnitude.

Thanks, but no, I didn’t mean that one. Yes, that is a different magnitude.

Up to performance phase 4, in my opinion, the architect is almost always the better solution.

Ui, I just overlooked that, but I can't leave it like that: we should not "encourage" anyone – not even by misinterpreting reading – to hire an architect only up to performance phase 4. That would always be half a job.