Wall crown external window sill with natural stone insulation

Hello,

the insulation under the exterior window sill with natural stone is only 1 cm for us. The exterior window sill itself is 3 cm.
What do you think about this? Is this within the scope of DIN 4108-2?

My expert says that this is far too little with WLG 035. The general contractor does not see the mistake and wants to charge me for possible additional costs.
Construction is being done with T9 stone 36.5 cm masonry.

Here is a picture of it. Does anyone perhaps happen to know what kind of product this is?

Can't anyone say anything about this?

Can't anyone say something about this?

It could be something like a Jackodur XPS board.

What do you think about this? Is this within the scope of DIN 4108-2?

No idea. What does the DIN say and how was the detail planned and energetically calculated?

My expert says that is far too little for WLG 035.

What is his reasoning?

The general contractor does not acknowledge the error and wants to charge me possible additional costs.

What does the construction specification or the execution planning say?

Could be something like a Jackodur XPS board. No idea. What does the DIN say and how was the detail planned and energetically calculated?

I just don't have a current version of DIN 4108 Supplement 2.

I just don't have a current version of DIN 4108 Supplement 2.

Sorry, me neither. I can only offer you an old version - but that doesn't help. But if your expert says that 10mm is too little, he will have referred to the DIN and seen the justification for his statement there.