What to do about the vapor barrier?
I am currently using a formerly unheated basement room as home office. The room is not properly insulated and rather hard to keep warm. I am thinking about installing a nicer floor and insulating it to make the climate more pleasant. The floor is currently bare concrete and I assume there is no vapor barrier under the slab. About 50% of the room is below the ground. We live in the Arctic, so the temperature ranges from about -35C to 25C, and it is mostly considerably colder on the outside than inside. I don't have much experience and am on a very tight budget.
The initial idea was to lay out PE foil as vapor barrier, build a wooden grid (60cm wide) to fill with glass or rock wool and to install wooden planks on top to walk on.
I am very unsure about the materials and vapor barrier thoug.
According to previous replies, I would end up with trapped water under my foil without channels to escape if the foil was placed directly on the concrete. As I can not build a pit, that makes me consider to ditch the vapor barrier altogether, to allow some ventilation, but that seems to eventually soak my materials.
I am not primarily concerned about the materials as in bent wooden floor planks after a few years. I am mainly concerned about mold, I don’t want to make the room a few degrees warmer but trade it for smell or an unhealthy environment.
I have attached an artistic masterpiece (sorry!) of what I mean and hope that someone might have a pointer what you would do.
I am still lost and would appreciate any help, I am also open to different materials!