Insulating a barn for later use as living space

Hi,

we want to convert a barn into living space.
Key data:
- Living area above the basement ceiling (entrance area)
otherwise on the 1st floor on a reinforced concrete slab
- 24´ exterior walls plastered
- pitched roof structure

Now, my father has always been of the opinion that he wants to install a pre-wall from the inside, which is ventilated by drilling/slitting holes at the top and bottom to the outside in the load-bearing wall. As a wall, for example, PU rigid foam / cold storage panels, clad on the inside with gypsum plasterboards.

The architect, who so far has only had discussions with my father, is not opposed to this idea and thinks it’s okay.

There really can be no moisture behind the wall anymore, but I have some concerns:
- The load-bearing wall completely in the cold area
- Insulation is not applied to the load-bearing wall at all
- Reduction of living space
- Rooms cool down quickly
- Summer heat protection = 0, as nothing massive can store cold

My questions:
- How much insulation may be applied from the outside on neighboring properties / must be tolerated or what other options are there?
- How would you insulate roughly with what and approximately what thicknesses?

Additional info – the floor is also to be laid with PU rigid foam and covered with concrete as an insulated floor. Total height 200 mm
The roof – insulation between rafters with glass wool (140 mm), insulation under rafters – PU cold storage panels / Rockwool panels (100 mm)

Thanks already for your answers

Hey community,

unfortunately, I haven't received any response so far. Did I formulate my questions incorrectly? Too much text? Or perhaps I was already trying to answer them myself while asking?

I am not an expert. The knowledge I think I have is self-taught. If someone has a question in the woodworking field, I can probably answer it immediately. But here, I am a layperson.

Therefore, I kindly ask you once again, following the motto good or bad, to give me a brief third opinion so that I can either comply or voice my concerns.

Thanks to you in advance

Best regards Mirko

Hello,

Have you already inquired at the building authority whether the conversion of the barn is even permitted and approvable?

I would generally forego internal insulation. How do the setback areas look so far? Are there any at all? Boundary development?

Regards

Hello and thank you for the response

We have not inquired with the building authority yet. The architect told us that in the current form this does not pose a problem.

As far as I have researched and received advice, there are major problems with installing external insulation if the boundary runs along the wall.

I am attaching an aerial photo. The orange-colored roof is the part that is to be remodeled. To the left is the street and below is the mentioned neighboring property, where you can still see a shed. The neighbor’s residential building is about 20m from the boundary.

Best regards

Mirko

I am already predicting now that it is more cost-effective to build a new energetically and building-physics optimized shell than to invest many hours and structural compromises in the existing construction. The limitations of the existing static elements and the current roof construction alone restrict you too much. In contrast, you plan without limitations according to your individual ideas and build something fundamentally new in the same place.

Best regards

T.H.