Changing floor, insulation?

[Mikaelw86]

Hello.
I'm renovating my house built in 1954. I'm working on tearing up the floor in the kitchen to make it level. It dips 2 cm from the highest point. Then I'll install underfloor heating pipes for a future extension.

Should I remove all the sawdust and insulate with something else, if so, what?

I first thought of laying battens for underfloor heating and parquet over them, but I see it will be wrong considering how I plan to lay the parquet floor. So maybe it's smartest to go with grooved floorboards. Can I lay them directly on the joists? Or do I need to reinforce more than that?

 

[huggan]

Hygroscopic insulation is preferable, e.g., ecofiber, so that you retain the property of the insulation being able to absorb excess moisture.

 

[Mikaelw86]

Never heard of it. Will have to look it up. But should one replace the insulation or can the sawdust remain under the underfloor heating?

 

[huggan]

You don't have to replace it, but it has a lower insulation value compared to today's insulation. How deep is the insulation?

 

[FG]

Is there a heated basement underneath? I would have at least changed the insulation closest to the exterior walls, as they tend to be drafty in old houses. In the pictures, the sawdust has also settled significantly, so the floors are drafty.