Exterior wall for KFW 40 (+) with or without ETICS?

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Structure-borne sound is also transmitted through a hard covering. The insulation between rafters is only effective for soundproofing up to 100mm. The decisive factors here are the flexurally soft shells. A roof truss will also not be decoupled. An exposed roof truss excludes soundproofing in the rafter area.

What is relevant here is not airborne sound unless you live near an airport, but structure-borne sound.

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Structure-borne sound is also transmitted through a hard covering. The insulation between rafters is only effective in soundproofing up to 100mm. What matters here are the flexible shells. A roof truss will not be decoupled either. An exposed roof truss excludes soundproofing in the rafter area.

What is relevant here is not airborne sound anyway, unless you live near an airport, but structure-borne sound.

That is unfortunately wrong. Airborne sound is the big problem, even without an airport. You will hear every airplane at 10k meters altitude inside your house. Every bird and rain/wind, of course, as well.

Just google it. What is missing in the execution is mass and spring.

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Both can only be on the rafter roof :)

"Masse" is also just a construction method, which is not relevant here anyway, since it is not a solid roof.

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Both can only be on the rafter roof :)

Masse is also just a construction method which is not relevant here anyway, since it is not a solid roof.

I do not understand that. Even a non-solid roof should have Masse. And of course, the insulation lies on the visible sheathing/rafters, where else.

The first hit when you google sichtdachstuhl and PUR: “1989 polystyrene insulation boards were gradually replaced by polyurethane flat roof insulation systems from x, y, t etc. Advantages of PUR or PIR insulation elements are better insulation with the same insulation thickness. The weaknesses in soundproofing and wind tightness, however, remained.”

You can surely manage to google that (-;

@Bookstar

The insulation under a hard shell like roof tiles serves to protect against structure-borne noise. Alternatively, only the base battens can be equipped with a rigid insulation board on the rafters.
That would be the decoupling. However, even that is a circumstance that is usually not required in a noise protection certificate, as the attic is often the final residential unit.

If someone wants to do something for themselves, they can only install concrete wood fiber boards on the visible rafters, or carry out these with concrete slabs between the
rafters. However, this does not yet provide 1400 kg/m³ of mass.
In terms of purpose, I would not see airborne sound insulation in private housing construction, but rather heat protection. Except in cases of special airborne noise emissions, such as at airports.

In practice (Frankfurt Airport), I do not see the roof as a problem at all, but the windows and other openings.
Main problem is open windows in summer for ventilation when there is no ventilation system.

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No commercially available insulation alone will be able to cover low frequencies. Even if thermal protection is often accompanied by the noise protection certificate.
However, often different materials in the composite cover the individual frequencies. Whether on the rafter or between them will not make much difference.
Without knowing an expert opinion.