Eco house advice needed!

[Vortex2]

Advice needed please :
We have built an eco house.
The roof and walls are massively insulated and hopefully air tight!
Doors and windows are all triple glazed
A heat pump provides heat & hot water.
However we have no vapour barrier/moisture barrier in the floor .. we weren't sure what flooring we needed/wanted.
The bare floor is currently: crawl space (inaccessible) -> lower ply layer -> 20 or so cm of rockwool -> upper ply layer.
Both ply layers have 'cracks' as they are clip togther Lego-like pieces. Clearly NOT air tight which ruins our eco house goals!
We now have enough funds to get some flooring fitted.
We need a vapour control layer above the current Lego floor but below the new flooring.
What sort of vapour layer material should we be looking it?

[Mark]

I can't help you..., but maybe worth dropping these an e-mail ?

ENERGY HOUSE 2.0 PROJECT:
https://energyhouse2.salford.ac.uk/