Promasil (insulating stones), which coating?

Behind the wood stove, next to the chimney, there will be an 8cm thick Promasil insulation so that the wooden stud wall does not get scorched. The material is easy to work with because it is quite soft. I am thinking about what I could use to treat the surface to make it a bit smoother and more impact-resistant. So far, I have not found any suggestions from the company itself. Does anyone have an idea?

I would put a board with a higher bulk density on the surface to make the whole thing less shock-sensitive. If you want to stick with Promat, possibly use Promatec. Alternatively, a Fermacell board. I can't say anything about surface treatment because I always only need the stuff in invisible areas and don't do anything in that regard.

Who suggested the Promasil in that thickness to you? I would ask them in detail.

yes, a flat surface would be simple(r). What I'm looking for should also "go along" with curves (I haven't done the shaping yet, but towards the ends the surface should be flush with the surrounding wall).

The material and thickness were suggested to me by the chimney sweep. (I have always found chimney sweeps to be particularly nice and cooperative).

One idea is mosaic tiles, but I would prefer something like a filler ... I am still looking for possible solutions