Pipe insulation vs. insulation panels

[*]~0.5cm welding membrane
[*]6+5cm Styrofoam insulation boards
[*]3cm insulated tack mat
[*]6cm screed with underfloor heating pipes
[*]1.5cm floor coverings

Hello everyone,

a question regarding insulation filling on heating pipes.

We have the following 22cm floor construction on the concrete slab on the ground floor, consisting of (from bottom to top):

[*]~0.5cm welding membrane
[*]6+5cm insulation boards made of Styrofoam
[*]3cm insulated stapler mat
[*]6cm screed with underfloor heating pipes
[*]1.5cm floor coverings

6+5cm insulation boards because most pipes on the floor slab are 4-6cm high and we wanted to lay the second layer of insulation boards continuously. Water and heating pipes are to be compensated with Mehabit-bound filling up to the top edge of the first layer.

However, on the floor slab there are also 2 heating pipes including insulation mantle with 8cm height, how do we proceed here?

Current plan: We lay both layers up to the pipes there, then fill up to 11cm and then simply put the stapler mat on top.
Is that okay or should there definitely be a more stable insulation board under the stapler mat?

Best regards

I first had a complete 5 cm insulation layer installed with WLG 032 without interruption. In the second insulation layer above it (laid crosswise to the first insulation layer) with WLG 032 are the water pipes, of course insulated. On this second layer comes the 3 cm tack mat.

Just put the stapling mat on. You can be completely relaxed about that (unless you need 30cm wide channels for the heating pipes).

So you mean to compensate the 3cm with fill material, right?

I hope I can lay the 2cm insulation evenly on top. If not, would that be a problem with leveling fill across the surface?