Exterior wall insulation or perimeter insulation? Change by general contractor

15 cm are my interior walls, I even believe 17.5 cm. You’re building in Hamburg. You will spend a lot of money. Then build yourself something proper. Forget all the [kfw] stuff, take the classic 24.5 cm Ytong or comparable from porith or hansa beton. In front of that mineral wool. In front of that the clinker. Then you get a house that will stand for 100 years and hold its value. You also won’t get poor heating such a shack. My advice. Karsten

Are you sure?

With ytong, the standard for interior walls is actually 11.5, except for the load-bearing ones which are 17.5

I mean the load-bearing ones. So his exterior walls are thinner than my load-bearing interior walls. And that is not okay. Karsten

I do think it's okay, someone must have had a reason. I wouldn't want it, but I think technically it will be okay.

Of course that's okay. But there are probably barriers in the mind. 15cm is said to be too thin but a normal KS exterior wall, for example, is only 17.5cm. Dramas are staged here over 2.5cm. Interior walls are regularly built 11cm thick and covered with sockets, but the 15cm exterior wall will surely collapse. These are completely normal wall thicknesses in functional walls. The structural engineer simply knows better than forum users.

That is how it is