Planned house construction - garage/workshop below, living area above

Hello everyone,

I want to build a house next year. The lower level should only have storage space for a motorhome, cars, tipper truck, technical room, small storage room, and the entrance including the staircase. The living area will be upstairs. The floor area is about 14.5x12m, and the room height downstairs should be 4m due to the motorhome (3m entrance height) (1.5m of which disappears into the slope). Upstairs, I want a visible roof truss and about 20 degrees roof pitch.

Now I have a few questions:

Downstairs, I might use double concrete walls. Has anyone had experience with this? How does KFW funding look if I only insulate the ceiling? Or would you insulate everything? The roller gates would then be the weakest link in terms of insulation.

Upstairs, filled Poroton should be used. Are there big differences between the various manufacturers? Schlagmann, Wienerberger, Unipor, ..

On top of that comes a visible roof truss. Would you choose a double roof truss with insulation between the rafters or use the prefabricated panels? Since I want a KFW loan, the question arises whether insulation between the rafters is sufficient?

Many thanks for all the answers in advance

Regards Niederbayer

Concrete double walls are also available with internal insulation. This is called Thermowand by most manufacturers. Maximum heights are usually around 3.5 meters. How about budget and approval feasibility?

Underside uninsulated and top insulated would be the direction I would take first. The underside of the living area will then be the challenge. Entrance from below or from the side?

Concrete double walls also exist with internal insulation. For most manufacturers, this is called Thermowand.
Maximum heights are usually around 3.5 meters.
How does it look regarding budget and approval feasibility?

Thermowand: Installation possible but then I constantly have condensation on the roller doors and the price is also steep.
Budget: Fits
Approval feasibility: According to the building plan, there is nothing against one floor being 4m high.

Uninsulated at the bottom and insulated at the top would be the direction I would take first. The underside of the living area will then be the challenge. Entrance from below or from the side?

Exactly. I have headaches with the transition from the walls to the ceiling -> dew point in the concrete.
Entrance below. But the stairwell doesn't necessarily have to be heated.

The KfW requires the Energy Saving Ordinance. In this case, the DIN 18599. Through the zoning, you have separated the non-residential area from the residential area.