Originally Posted by angrysparrow
I was indeed talking about an UQ.
If you have a vapor barrier on the outside of an UQ, but not one on the inside....then your body moisture through radiant heat will enter the UQ and not be able to escape because it is stopped by that vapor barrier. Do that long enough, and you'll wet the insulation, thus reducing it's efficiency.
The rule of thumb with VB's is that if you use one, it goes nearest your body with regards to the insulation. If you use two, then you can place the second one on the outside, as a wind break.
I used a PU coated poncho as a weather shield on the outside of the UQ when it became obvious the temps would drop a LOT, to keep a little bit of a breeze from leaking through - there was ice on the UQ shell.
Was almost - but not quite - cold in the hammock. No rain, no dew - the ice was my insensible perspiration hitting the barrier and freezing on the quilt. There was just a little air gap between UQ and poncho.