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

I will take some pictures tomorrow and upload them; the ones I currently have do not clearly show the situation.

In principle, a [Bauanfrage] would certainly be a sensible approach, but our situation requires a somewhat different procedure, so we would first like to consider the floor plan. However, in the coming days we will also discuss the further procedure regarding the building permit again with the aforementioned architect. Due to cost reduction, we would prefer to use the architect mainly for the building application and to develop the floor plan ourselves as much as possible. I know this is often viewed negatively here because architects have, after all, studied specifically for this, but I hope for your understanding in this regard.

Just so much in advance: My boyfriend and I would like to convert a part of the barn on his parents' farm into a residential house. Therefore, we are not as free in terms of dimensions, style, design, etc. as with new construction and have to work with the given conditions. The goal is to convert the barn part into a single-family house for a family with presumably 3 children. However, the house should also be able to be rented out later, if necessary, as 2 apartments. The background is that the existing residential house, in which my boyfriend's parents live, is less suitable for renting out,

The reason why I am not, as usual, coming with a link to a similar twin case around the corner now is solely the current time. But one would have to look back less than a year here.

Due to cost reduction, however, we would like to primarily use the architect only for the building application and develop the floor plan ourselves as much as possible.

That is the most unbelievably wrong place to save money – besides, the architect’s work consists of only about three percent of floor plan drawing.

In principle, a preliminary building inquiry would certainly be a advisable approach, however, our situation requires a somewhat different procedure,

How can that be? What does the floor plan have to do with a possible buildability/rezoning? For the preliminary inquiry, you only need one page of text + maybe a photo of the existing condition and you will get certainty.

The reason why I’m not coming around the corner now as usual with the link to a similar twin case is solely the current time. But one would have to look back less than a year here.

This is the most unfailingly wrong place to save money – by the way, architectural work consists of only about three percent of drawing floor plans.

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 is a completely different magnitude.

In the OP’s case, the width of the barn seems to correspond with the building wish.

Up to service phase 4, in my opinion, the architect is almost always the better solution. Especially since the mentioned architect is said to have experience with such conversions. When converting the barn, you probably won’t find a contractor who can cover the rest well.

This is related to the fact that, according to our architect, we first need to partially bring the barn to the condition of "worth preserving building fabric," since in its current state we probably would not receive approval. Therefore, it is necessary to first renovate parts of the barn (which is possible without a building permit) and then change its usage. For example, this concerns the northern wall, which consists of timber framing that must be completely renewed. However, so that we do not unnecessarily create obstacles for ourselves for the later renovation during this initial renovation (for example regarding the division of the timber framing), we would like to work out a rough idea of our future floor plan beforehand. This calls for a sensitive approach, which will of course be coordinated with the architect...

How can that be? What does the floor plan have to do with a possible buildability/re-zoning? For the preliminary inquiry, you only need one page of text + maybe a photo of the existing condition and you will get clarity.

In the case of re-zoning in the outer area, I would want to use some technical arguments. That's where you save in the wrong place. ;) how steep is the roof pitch? The upper attic will hardly be usable. I have 10 m width and 45 degrees RP 1 m knee wall. That leaves 1 m with over 2 m height usable. Possibly plan technical equipment there. Storage space is also possible. How about the budget? The question remained unanswered.