I find it rather arrogant that I supposedly only have "occasionally" truly useful tips or that my writing style is empty of content. On the contrary: I rarely just say that, but often explain very thoroughly why something is a fact – so no one has to believe the all-knowing 11ant blindly, but gets it explained in a comprehensible way, gladly also understandable for laypeople anytime. For a physics pro-seminar to debunk the myth of sand-lime brick as the only sharp dog against the evil noise, however, the average layman usually does not have the necessary background.
I am also often misunderstood / considered unfriendly in real life, which is inevitable in communication across the Asperger ./. neurotypical language barrier. And on the internet, where the acoustic, body language, facial expression, etc. dimensions are simply missing in purely written form, I have to endure correspondingly more misinterpretations. But should I really refrain from sharing my expertise just because my Berlin bluntness is taken the wrong way in standard German?
The OP has a misunderstanding with his general contractor (GU) that emotionally looks like a problem, nothing more. "Fault" is a big, harsh and wrong word for the contributing causes on both sides of a misunderstanding. The fact is that there was a change between a drawing interpreted as the agreed construction contract subject and a preliminary version of the building permit drawings, which the OP did not expect as a layperson and which irritated him. He is only "at fault" for his attitude towards the GU, feeling "fooled" and filing a consumer protection asylum request here in the forum, which is, however, completely unnecessary (as said, regarding the change of the cross gable, the GU has already proven that he is by no means a sly customer eater). I then explained to the OP the technical context in which the conflict exists from a construction-technical point of view and that a draftsman – who is as much a layperson as the OP himself – is not trained to recognize this complication early on. Just as the OP probably did not consciously and maliciously give the GU an impossible task (build the exterior walls in EH40 and with sand-lime brick and in caliber 425), the GU probably didn’t rub his hands (oh fine, I fill the base area with cheap bricks and save expensive interior finishing through reduced living space, he wants it that way). Rather, the GU fulfilled the customer wishes EH40 and sand-lime brick, which in the magic triangle leads to the sacrifice of the third parameter caliber 425, and professionally increased the total wall thickness by a quantum leap to caliber 490. Up to this point, the OP is quite in agreement with the GU. Then the GU only – and here I am convinced, every insinuation of malice is misplaced! – made, with a 50/50 chance, the unexpected / other (calling it "wrong" I find inappropriate here) choice of placing the difference on the room side. The OP would have preferred it on the outside. That – and not a jot more – is already the whole fuss here. There is no reason anywhere to dig up a hatchet. Clarify the misunderstanding, laugh together, and shake hands – all done in a moment.
My expertise and my practice as a moderator (and in serious cases a client-side advisor) then motivated me to suggest to the OP that he could completely defuse the conflict he unknowingly called forth by simply swapping the constructive wall builder without disadvantage (because sand-lime brick at this point compared to aerated concrete, in contrast to an especially unfilled porous brick I would see that differently, offers no advantage but a massive U-value handicap). However, he does not want that. Apparently, his feeling of having been deceived is preferable to him over recognizing in a solution-oriented way that no one wishes him harm and that the (in my opinion better) way out lies outside the battleground. There are enough experts so I don't have to believe that without a second opinion. I do not put on the shoe of an arrogance diagnosis for this.
Thank you for your contribution.
Unfortunately, you misunderstood me. The order before contract signing was a KfW 40 single-family house made of 17.5 cm sand-lime brick + insulation (I did not specify any dimensional requirements here) + 11.5 cm clinker brick. I did not know how thick the insulation had to be to achieve KfW 40. I left that to the general contractor. Subsequently, he created the colorful drawings you have. I trusted that these drawings already corresponded to the wall construction according to KfW 40 requirements and that we could be happy with the indicated areas. I never wrote that the entire wall construction’s width should fully correspond to caliber 425. After signing, the GU sent me the info including building permit drawings that previously a 425-caliber wall structure was calculated, which unfortunately has now been widened by 6.5 cm:
"According to the requirements for KfW40 and the (preliminary) specifications from our structural engineer, we have increased the exterior walls from originally 42.5 cm to now 49 cm, furthermore, interior walls on the ground floor have been planned with b = 17.5 cm based on statics, which results in a slight loss of actual living space, as well as small shifts of interior walls following the static requirements. This is, however, strictly necessary."