carpeting and linoleum tiles over slab

[vinman]

hi, guys,
Our back room which also leads out into the back yard was originally a screened in porch.
the previous owners turned into another room. The floor is a cement slab.
My wife uses it as her den. (i get the basement..."whatever makes her happy, makes me happy")
we're redoing the whole room over. presently, the carpet is over the slab.
Our plan is half the room new carpeting and probably those linoleum tiles where everybody comes in and out from the yard.
The question is, should i put down some kind of subfloor. That room does get chillier than the rest in the winter and i don't know if the cement floor contributes to that. if i do put a subfloor, should i put a layer of those styrofoam sheets between the cement and the subfloor? I have also read that some people put felt paper over the subfloor.
Lastly, if a subfloor is necessary, would liquid nails or one of those adhesive types be sufficient to fasten the floor down. Nailing into cement even with masonry nails is a $#%^%.
any suggestions?
thanks.

[tooltroll]

Is moisture an issue? How cold is your winter? If it was me, with our polar winters, I'd lay 2x4 floating sleepers with foam between, vapour barrier, and OSB screwed to the sleepers. If you can't afford to lose a couple of inches height, I've seen OSB laid directly on 1/2" foam, but this won't allow as much insulation. I'm always kinda leery about putting finished floor materials directly on a slab...

[Sweep]

Assuming there is good drainage around the house, the biggest issue is moisture vapor rising up through the slab and being trapped under the floor finish. There are many underlayment systems and mositure barrier made to prevent this problem.

One is:
http://www.cosella-dorken.com/products/floor/products/FL.php

[rabadger]

This could be a great application for hot water radiant heat.

Put down a thermal break, and quick trak sub floor.
how big is the room? A lot of windows?, Insulation in the walls?

You can carpet, tile or use wood. You won't be able to get her out of their in the winter.

[kadoka]

If you have an outside entrance to that room, you may not have a lot of choice. Adding anything on top of the slab may raise your floor higher than the door threshold.