Which way round do I lay this laminate underlay?

[FloppySock]

Hi all,

I've got this white foam laminate underlay which has film on one side.

Does the film go against the floor or up in the air?

Also am I best taping the joints or not bothering? And I assume the underlay doesn't need securing down and the laminate on top will ensure its all secure?

Pics attached, thanks. Phil

 

[Bonni]

I've always assumed the the film is a vapour barrier so film side down. Taping the joints just stops it flapping about whilst fitting the laminate.

 

[foxhole]

The film is for an overlap to give unbroken underlay.