Insulate basement exterior wall due to 10,000 houses program

We have applied for a 1.5-liter house under the 10,000 houses program that [Freistaat Bayern] has launched. To achieve this, we need a very high insulation value in the basement. That would not be a problem if we could simply apply any amount of exterior insulation. But for our house (timber frame construction) to still rest securely on the basement, a maximum of 12 cm of insulation is possible. If we now applied 14 cm, the basement would protrude. My idea was to simply insulate 2 cm more at the top as well. But the builder says that 8 cm of wood fiber insulation is too heavy for the brackets. His suggestion would be to apply interior insulation in the basement. I am not so enthusiastic about that. Does anyone have an idea what other options there might be? For example, 12 cm basement insulation with a better insulation value?

Better insulation value would be one option... who is calculating or supervising the construction? It all sounds somewhat vague - without a concept, just a little here and a bit more there and somehow it fits then!?

I still don't understand why the ground floor should sit on the basement insulation – the perimeter insulation doesn't have any structural function and could therefore be built as thick as desired.

At least with solid construction that's how it is – or am I misunderstanding something?

The wooden house is to stand on the basement. If the basement has 12 cm of external insulation, but the wooden house only has 6 cm, the studs need to protrude slightly so that the facade of the basement and house are flush. Unfortunately, I have only ever heard that this does not work or is not enough. But unfortunately no solution, except for internal insulation. Is there basement external insulation with a value below 0.35 WLG?

Wait, does your basement stick out of the ground? Then I would understand that :)

Wait, does your basement look out from the ground? Then I would understand that :)

On one side it sticks out completely.