New floor with insulation

[philrosenberg]

Hi
I'm renovating a 1930s property. All ground floor floors are suspended timber except the kitchen which is (was) concrete. I have just dug this floor up to lay a new insulated floor (I will be insulating under the suspended floors too). My initial thought was to put down a damp proof membrane, then blind with sand, then 100mm Kingsman then a vapour barrier then a floating timber floor.

Now however I'm worrying that maybe I should lay concrete under the insulation. Is this necessary? Or can I just go with bare earth?

Thanks in advance

Phil

 

[John D v2.0]

You would need compacted hardcore not just bare earth. Then dpm, insulation, screed or similar then you're done
We had similar but just insulated between the joists and left the ventilated void.