what is the fabric they use to make a plaid shirt
Sometimes flannel, sometimes cotton.
NoVapor barriers are only placed against the conditioned spacePlacing it on top will trap moisture and cause all kinds of problems.
More info is neededFor example: do you mean the insulation on your attic floor between the joists? If so definitely don't put a moisture barrier over itIf you mean something else - well it would all depend.
