Screed with or without unused dimpled sheets?

Hello everyone,

in the attic, we have underfloor heating in some rooms and ceiling heating in other rooms.

Now, by accident, studded plates for underfloor heating were installed in the bedroom (where there is ceiling heating). In these areas, only partial new screed should be added, but no underfloor heating.

Now the screed contractor says we will just leave the studded plates (under the studded plates there is roughly one cm of polystyrene insulation boards) in place and fill with screed.

We obviously don’t damage it that way, but wouldn't it still be better to remove the plates and just pour in full screed?

Many thanks for the help!

Hello questioner.
What’s done is done!
Do it as suggested. The screed mortar is simply applied over the [Noppenplatte]. There are absolutely no disadvantages because of this!
Regards: KlaRa

Under the studded plates, there is still Styrofoam insulation. Does it matter if the screed runs over the Styrofoam? I'm asking because the studded plates are laid quite loosely.

The studded panel, as you described and also installed on site, was intended to accommodate a screed mortar. Whether with (as usual) heating elements or not, this does not change the final situation! The screed mortar cannot run onto the impact sound insulation if the studded or system panel was installed properly. If it was (which here is assumed only hypothetically) not installed properly, then the screed mortar would have reached the impact sound insulation even with heating elements. Putting theory and assumptions aside: Have the screed installed above the system panel – and that's that!
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Regards: KlaRa