ᐅ Screed Protective screed Attic on concrete slab

Hello everyone,

I have now insulated my attic (vapor barrier and 2 x 10 cm (4 inches) Styrofoam).
According to my construction company, a protective screed should be applied on top.
Does anyone here have experience with how much something like this usually costs?

The area is almost exactly 100 sqm (1,076 sq ft).

Thank you very much.

Protective screed refers to a function, not a specific material. So, what exactly is going to be installed?