Vapor Barrier and Air gap Ideas

[GotSmart]

Pure water, (no minerals or salts), does not conduct electricity, but it does conduct heat.  If water did not absorb heat easily and lose it easily, it would not be pumped through heating and cooling systems. Your theory that if something does not conduct electricity, it will not conduct heat energy is flat out wrong. 

Boy do I have an electric fence for you to pee on!    :angel:

Water is a great way of shorting out power systems.

A live wire in a pool will kill anyone stepping into the pool.

 

[TrainChaser]

DannyB keeps arguing about 'pure water', but how often do you run across THAT??? If water is getting behind a surface, then dust is, too, so if the moisture was 'pure water' to start, it isn't soon.

Sometimes Scientific Theory (or even facts) butts heads with Real Life.

If there's anything 'pure' in van camping, I would like to know what it is! *laughs*

 

[TrainChaser]

I've learned a lot here: I certainly didn't know about the dead-air space, but it makes sense, now.  I will need to insulate against heat and cold, so it's bubblepak/reflectix/rigid foam.  Got it!

One thing that puzzles me a bit, though, (if I'm understanding it correctly) is all of the conversations about sealing the dead-air space.  In a van, I simply don't see a way to do that.  Moisture is going to work its way in no matter what you do, isn't it?  And plastic is hardly a moisture barrier -- at least, that's what Burt Gummer says!

Venting seems of crucial importance to me.  I've seen how different a bare, uninsulated van can be when it's not (top) vented, and when it is, both hot and cold.

 

[akrvbob]

Let's stay on topic which is not water's conductivity.
Bob

 

[GotSmart]

I've learned a lot here: I certainly didn't know about the dead-air space, but it makes sense, now.  I will need to insulate against heat and cold, so it's bubblepak/reflectix/rigid foam.  Got it!

One thing that puzzles me a bit, though, (if I'm understanding it correctly) is all of the conversations about sealing the dead-air space.  In a van, I simply don't see a way to do that.  Moisture is going to work its way in no matter what you do, isn't it?  And plastic is hardly a moisture barrier -- at least, that's what Burt Gummer says!

Venting seems of crucial importance to me.  I've seen how different a bare, uninsulated van can be when it's not (top) vented, and when it is, both hot and cold.

If you can keep air flow going, the moisture will not cause the huge problems.

Last year I converted a bare 1/2 dirt basement into a media room in CA.  The first thing called for was vapor barriers.  I stapled up a plastic sheet, and the building inspector was pleased.  :huh:

By controlling air flow the battle was won.  Put in a roof vent and suddenly the game is changed. 

Burt don't know his Bo Diddly.