Insulate intermediate floor when using underfloor heating in bathroom upstairs?

[Novisfixaren]

In the process of renovating an old house. There's something like "bark" as insulation in the intermediate floor.

Plan is to build a bathroom upstairs with tiles and electric underfloor heating beneath. The question is, do I have to insulate the intermediate floor or should I leave it as it is? What's customary?

See image:

 

[larsbj]

Insulate! great for warmth, but especially for soundproofing.

 

[Novisfixaren]

Let the bark lie and just put some regular insulation?

Does the insulation have any significant impact on the electric floor heating I plan to install in the bathroom?

 

[larsbj]

Yes, let the bark remain.

Most of the heat goes where it should, with insulation in the floor.