Storage space with concrete floors

I should appreciate your help on the following:

We are going to be leasing newly-built storage space while the
building we are acquiring for our new library and museum is under
renovation. The storage space is on the ground floor. The flooring
is concrete. We plan to store our art library (approximately 20,000
vols of art reference), paintings and works on paper there. For this
purpose, we plan to set-up (raised off the floor) shelving units to
store all of the items which for the most part will be packed in
crates, boxes, etc.

A colleague just informed me that the concrete floors will tend to
absorb large amounts of moisture, and that nothing sensitive should
be placed/stored *directly* on the floor. This remark raised a
concern that the moisture might even affect the items stored up on
the shelving units--especially books and works on paper.

My question to the members of the list is: Will concrete floors (the
supposed moisture they absorb) pose a threat to books, works on
paper or even paintings if those items are stored up on the shelves?
Are there any special steps that would need to be taken? Do we need
to cover the floors?  Again, I want to mention that the space is all
on the ground floor, i.e. above grade, but the concrete floor is (I
assume) laid over the ground. Is the moisture absorbed from the
ground below, or the air above the concrete floor? Or have I been
altogether misinformed about concrete floors absorbing moisture?

We are about to move into the space, and need to know if
preparations/treatments are necessary *before* we transfer works on
paper, fine art reference books, etc.

Mark Ast, Ph.D.
Curator
Museum & Library of Barbizon & Pre-Impressionist Art

                                  ***
                  Conservation DistList Instance 10:3
                  Distributed: Thursday, June 27, 1996
                        Message Id: cdl-10-3-002
                                  ***