Should I add a vapor barrier in my attic?

Question

We are finishing our attic and have already put in the paper faced insulation. We have now been told that a plastic vapor barrier is needed on the outside of it. We are unsure what to do because of all the conflicting answers we have received. some people say it will cause moisture to build up in the insulation. Is this true and do we need the barrier?

Answer 1

Yes you should. Sounds like a great idea. If you want it get it, if not, don't!

Answer 2

the vapour barrier should be on the warm side.here is a good read

http://images.google.com/imgres?imgurl=h...

Answer 3

You already have a vapor barrier on the paper faced insulation so you don't need another one.

Answer 4

The paper facing on the insulation acts as the vapor barrier. And additional layer of plastic will make it a bit more airtight, but isn't necessary.