[Spits] Moisture from a concrete floor?

[bill at gingerich.us]

   Greetings, All!

   Over  the years, I've heard various comments about moisture coming out
   of  concrete  floors and speeding the rusting process of metals stored
   on  it.   You  know,  like  a  project  car  sitting in storage for an
   extended  time.   So  my  question  is  this  -  Is  this,  in fact, a
   concern?  I'm  going  to have to store 2 of my projects in an enclosed
   steel  shed with  a  poured  concrete floor.  There will be no climate
   control,  just  Oklahoma  heat,  humidity, etc.   Should  I  seal  the
   concrete?   Put  down a piece of poly sheeting?  Buy one of those cool
   but  expensive  inflatable plastic bubbles?  Not worry about it?  What
   say you all?

   Bill Gingerich

   Newalla, OK