Concrete floor construction

[jesteh]

Is it ok for floor to be constructed in the following way
Sub-base - hardcore + sand
above that kingspan insulation board direct onto sub-base
above that visqueen sheet
above that concrete slab (no screed)

Specifically, I am not sure about PUR insulation board being put directly onto sand - not sure if damp is going to affect it or not.

 

[mravant]

Between the Sand and Insulation boad you will need a Damp Proof Membrane (DPM).

 

[jesteh]

Its already been done by builder with kingspan straight onto sand and then DPM on top.

 

[mravant]

We have just had this done and the DPM is in between the sand and insulation, on top of that, our building inspector asked for another DPM to be placed over the insulation before the concrete was poured as there have been cases of a reaction taking place when the concrete meets the insulation.

 

[Deluks]

Is it ok for floor to be constructed in the following way
Sub-base - hardcore + sand
above that kingspan insulation board direct onto sub-base
above that visqueen sheet
above that concrete slab (no screed)

Specifically, I am not sure about PUR insulation board being put directly onto sand - not sure if damp is going to affect it or not.

That is an acceptable method.
If no screed, I would expect the slab to have been troweled or floated. Unless a few mm has been left for self levelling.

It is also the case, as mentioned that concrete and inso should be seperated by poly.