Between clinker facade and roof: hornets want to settle

Honestly – I haven’t given much thought to the roof ventilation. In principle, the mineral insulation should be directly behind the stones, and the mineral insulation also begins there in the roof. I don’t know if air needs to be able to flow in anywhere. Where should it move there? Above the insulation is the underlay membrane. From the inside, we definitely placed a lot of importance on airtightness.

If I now staple perforated mats there, I probably haven’t gained anything, because the hornets will most likely build their nest directly on them—that’s certainly the perfect surface. You can also see on the stones that they apparently had already started there.

Regarding the topic of the "swelling tape," I can also mention that insects have definitely been active at the terrace door, gaining access there (see photo).

If I build a house again in this life, I probably won’t have it clad with bricks again. That is too complicated a construction with too many weak points. To bridge the insulation and the air cavity, all the windows had to be positioned very far outward so that they barely overlap with the shell construction, and then they were additionally fitted with these white strips. Elsewhere, people have already tried to lever the window out with a crowbar but only damaged the stones because they didn’t realize at all that the windows are anchored in the shell structure and the stones are only a facing shell. All very frustrating...

Of course, the points you mention are annoying, but:

1. most certainly do not have a problem with the "defects/weaknesses" you describe
2. I would always build with clinker bricks and see many more disadvantages in plastered houses
3. honestly, I doubt that the damages shown in your photo were caused by insects. These are clearly (?) "cutting injuries" in the swelling strip, caused by someone or something, but unlikely by insects? The latter may have only exploited the damaged/open spots afterward for their purposes!?

Regarding roof ventilation, I am certainly not the right person for well-founded comments. But even if you insulated from the inside and paid attention to airtightness, there can certainly be a "rear ventilation" in the structure beneath the roof tiles...

Someone must have nibbled away the material...

Regarding the roof: The mineral insulation is between the rafters. On the rafters lies the underlay membrane and on the underlay membrane the battens. On the battens lie the roof tiles with verge stones at both ends. Whether and where air circulates or must circulate there, I can't say exactly. In my opinion, we did everything correctly back then, it's been over 20 years.

Again about the windows: What would another solution have looked like, assuming that ten centimeters (six centimeters of mineral insulation and four centimeters of air gap) have to be bridged between the shell wall and the [Klinker]?

Google for gap mesh. That should not be a nesting ground for hornets or other wasps.

So your roof is already the insulation level (not the top ceiling). Is it heated? In my opinion, the attic should not be airtight as a room if it is not heated, because otherwise warm moist air would lead to condensation and moisture and eventually mold. To avoid this, a cold roof is usually ventilated somehow. And not only is the insulation ventilated but also the entire attic itself. I just don’t know if your gap up there could be responsible for that. In case of doubt, better close it with gap mesh. If you somehow find out from a real professional whether the gap is even supposed to be there (technical function), you could also consider closing it properly. But I wouldn’t just seal it up like that.

My upper floor is a knee wall with a 1.50-meter knee-high wall. On top of that sits a purlin roof with two foot purlins, two middle purlins, and one ridge purlin. The collar beams above the middle purlins are visible in the room. Everything is sealed on the inside, and of course it is heated inside.

I have such joint grids in the lower area of the clinker bricks, and also again at the top. So, each time in some vertical joints. But here we are talking about horizontal areas between the rafters, each about 60 cm.

Aha, ok. Then everything is fine. So it’s at most the ventilation behind the facade. I would also put joint mesh on it. Before that, a bit of Ardap so that everything that shouldn’t be there comes out.