Facade insulation: Insulation thickness vs. U-value

Hello dear forum,

I am in the process of renovating an old wooden house and would like to take advantage of the funding opportunities for energy-efficient renovation from KFW/BaFa. For this purpose, I have already hired an energy consultant and am trying to determine with him which requirements I have to meet. Unfortunately, I am not very satisfied with the cooperation with this energy consultant because it is very difficult to get the relevant information from him. Therefore, I am turning to this group in the hope that someone can help me out.

Specifically, the current question is as follows: The energy consultant told me that – regardless of the efficiency house standard – a certain minimum insulation thickness always has to be met. As an example, he told me that the roof insulation must always be 280mm – regardless of the type and quality of the insulation material used.
In my case, there is already 60mm of insulation above the rafters. Thus, I would have to add 220mm of insulation material so that the insulation is eligible for funding. However, in all the information I find, there is nowhere any mention of a minimum insulation thickness; rather, it always talks about the U-value of the component, which leads to different calculation results depending on the materials used and of course the thickness.
Can someone therefore confirm or deny that these minimum thicknesses exist, where they are described, and how the minimum thickness correlates with the minimum requirement for the U-values (0.24 W/m²K)?

Furthermore, one more question: I have heard that for the construction year 1982 the Building Energy Act [Gebäudeenergiegesetz] is not relevant. Is that correct and would this result in different limits for funding?

Thank you very much for your assistance!

As an example, he told me that the roof insulation must always be 280mm thick - regardless of the type and quality of the insulation material used.

Nonsense. During my studies, the law professor always asked so nicely, "Where does it say that?" You should ask that question too.
I achieve my necessary U-values for the 55 renovation house through a variety of materials with different thicknesses (which is obvious, the mineral wool 035 on the top floor ceiling must be 24cm thick for me, under the basement ceiling 10cm PUR 022/023 is enough).

Furthermore, another question: I have heard that for the construction year 1982 the Building Energy Act is not relevant. Is that correct and would this have different limits for funding as a result?

What counts is today and now. No matter when the house was built. If you want funding, you have to meet the criteria set today by the KfW. Quite simple.

You have to achieve the calculated insulation value, there is no set standard as a regulation. We changed it multiple times due to lack of building materials and each time the respective insulation value of the material was requested and adjusted.

In my case, there is still a 60mm insulation above the rafters. Therefore, I would need to add another 220mm of insulation material for the insulation to be eligible for funding.

What does "there is still" mean? Is it installed, which material? Maybe it would still make sense to insulate the roof more thoroughly. Ultimately, the energy consultant always adjusts various factors to achieve the required value, things like windows, insulation, etc. However, it seems to me that you should rather look for another energy consultant.