Pipe insulation vs. insulation panels

@ " " As I see it, you haven't really received a usable answer to your technical question so far. Your idea with the fill is good. But not in the order planned. That you know 11cm as the necessary build-up height makes things easier. 11cm minus twice the thickness of the insulation layer is the height with which you fill a bonded fill on the raw ceiling. The installation pipes are then embedded in the fill, the first insulation layer is cut out around the installation pipes. In such a way that the top edge of the first insulation layer is identical to the top edge of the installation pipes. Only then the entire floor surface is continuously laid with the second insulation layer. On top of this, the tack board. --------------------- Good luck: KlaRa

@ " "
As far as I can see, you haven't received a really useful answer to your technical question yet.
Your idea with the loose fill is good. But not in the order you planned.
Knowing that 11cm is the necessary build-up height makes things easier.
11cm - 2x the insulation layer thickness is then the height with which you fill a bound loose fill on the raw ceiling.
The installation pipes are then embedded in the loose fill, the first insulation layer is cut out around the installation pipes. And this is done so that the top edge of the first insulation layer is identical to the top edge of the installation pipes.
Only then is the entire floor area covered continuously with the second insulation layer. Then the tack board goes on top.
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Good luck: KlaRa

Hello and first of all thank you very much for the answer!

11cm - 2x the insulation layer thickness is then the height with which you fill a bound loose fill on the raw ceiling.

I didn’t quite understand that.
I will summarize the plan on the ground floor again according to my understanding:

[*]Pipes (2cm, 5cm, 6cm) were already laid on the floor
[*]I lay the first insulation layer (6cm) over the entire floor and cut out accordingly at the pipes
[*]The "gaps above the pipes" are then filled with bound loose fill up to the top edge of the first layer
[*]Then the second insulation layer (5cm) is laid completely and without gaps on top
[*]Then the 3cm tack mat goes on top

Is that correct so far?

If yes, then there is still one question regarding the upper floor:
Here we have rooms with only 2cm pipes, others with 5.5cm flat ducts and 2cm pipes, and finally the hallway with 8cm, 5.5cm and 2cm pipes.
Available here (ordered in advance due to feared price increases) are 6cm and 2cm insulation boards.
In what order should the boards be laid most reasonably?

Here I see 2 alternatives, which one would be preferred here?
a) Lay the 6cm boards first over the entire floor and cut out at the pipes, fill with loose fill over the pipes up to 6cm, and then lay the 2cm boards continuously on top (only the 8cm pipes would have to be cut out here)
b) Lay the boards depending on the room. Meaning: in rooms where only 2cm pipes lie, lay the 2cm boards first and then the 6cm boards on top; in all others, first the 6cm boards and then the 2cm boards on top. Just the question of how to handle the transitions between rooms, because somewhere you then have a transition?

And one last question:
By the way, can you recommend a loose fill? Currently under discussion are Fermacell and Mehabit, are there clear advantages or disadvantages of one product or the other?

Thanks in advance for the help

Does anyone have a few answers for me regarding the questions?

Does anyone have a few answers to the questions for me?

Well, the questions have already been answered by me, as far as the basics of the technology were concerned.
If you run different diameters of pipe installations over the raw floor area but don’t want steps between the rooms (which can be assumed), then you have no other choice but to transfer the highest point of all pipe installations to all rooms.
And that is only possible with a bonded screed.
The bonded screed always lies as the lowest layer on the raw ceiling, all other methods such as the “installation of insulation materials according to the Oberallgäuer woodcarving principle” (meaning: the pipe installations are artistically recessed in the insulation boards) are – to put it trivially – botched!
Find the highest point, use a rotary laser to transfer the height to the other rooms, fill up to the top edge of the highest point with bonded screed, and then – depending on the available build-up height in the room – lay a cover plate made of MDF and on top of that insulation boards in one or two layers with staggered joint offsets.
Regards and good luck: KlaRa

I join in here. We install our 90mm ventilation pipes on the concrete slab, meaning we will also have a "higher" construction. However, we have significantly less insulation above the ventilation pipes, meaning we will use

[*]100mm insulation (70mm loose-fill insulation and 30mm Styrofoam)[*]20-2 staple board and then[*]60mm screed

resulting in 180mm plus floor covering. Now I read from that the cutouts – which for us concern the Styrofoam boards – are rubbish... So better completely with loose-fill insulation? Then I wonder why the screed installer offered this mix? Edit: why the additional insulation above the pipes?

now I read from @KlaRa that the cutouts - which for us concern the styrofoam boards - are rubbish... So better completely in loose-fill insulation? Then I wonder why the screed installer offered this mix?

Answer: In the trade, such piecing work of the board-shaped insulation layer is jokingly referred to as "Upper Allgäu wood carving". For whatever reasons the screed installer offered these works, remains his secret. With a pumpable leveling layer made of cement, water, and sieve-controlled styrofoam beads, he would be faster and could work cleaner.

Edit: @Tushan79 why the additional insulation over the pipes?

Answer to this: The leveling layer is not to be confused with a classic insulation layer, as required under floating screeds. The manufacturers offer, so to speak, additional material properties en passant, but ultimately they cannot match insulation materials whose sole purpose is thermal or impact sound insulation! In this respect, the Federal Association for Screed & Covering (BEB) also demands that a continuous insulation layer be installed in the end.
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I hope the question could be answered with this.
Regards: KlaRa