Can I use this Insulation board?

[commando3]

I'm building a garden room and have now secured the ground frame/ joists.
Next stage is the insulation board between the floor joists which we all know is very expensive. However, I've been offered some pir board at a really good price but it has a grease proof like paper covering the foil which I believe is for dot and dab applications?,
So, question is, can I use this between my floor joists? The pir will be taped and a vapour barrier placed on top before the floorboards go on.
TIA

 

[23vc]

Can’t imagine it’d be a problem but can’t picture what the paper thing is