Sound deadener under the carpet etc. Will it trap moisture

[Spartan]

I never got the carpet put back in this fall but I was thinking about this tonight.  Will this sound deadener like dynomat trap moisture under it like the trunk mat traps water against the trunk floor.  Being in Michigan, humidity and temp swings happen allot,  I just didn't want it to rot the floorboards out our anything else it would be up against.  Just trying to get the winter projects lined up.

[Ghoste]

I would think it would.  It isn't porous like the carpeting is it?  Do you seal it to the floor or just leave it sitting loose?  For that matter, couldn't you shoot the floors with POR-15 anywhere you were going to lay that stuff first?

[bull]

I don't know but it's a very good question. I'm sure the manufacturer would tell you no but it'd be nice to have some info from an unbiased source.

[Spartan]

I am going to do the POR 15 thing first.  I am just worried about moisture under the mat.  My Avalanche is only 3 years old and I am starting to get rust in the bed (small but its still there) but there is always water trapped under the mat.  I ran the engine the other day w/o the interior in it and it sure does heat up so I would like to put a heat barrier and sound deadening but not at the cost of rotting out my floor pan.

[Ghoste]

Of course the bed is exposed to direct moisture as rains pours in.  The amount of moisture you would get from sweating in the humidity is going to be pretty small.

[Spartan]

actually, the bed of my Avalanche is pretty dry.  There is a pretty complex water removal system in it and the cover seals pretty tight.  The water under the mat is never gone.  After what the water trapped under my trunk mat did to the floor in the charger, moisture under a non-ventalated medium makes me nervous.