Another idea that might or might not be useful.  We were trying to keep
    moisture OUT, not in, in a concrete basement. As long as air circulated
    we were fine, but after sealing storerooms for Halon instalation (that
    was years ago before know known problems concerning Halon emerged) we
    began having moisture levels high enough that portable dehumidifiers
    could not keep up with it.  The solution was to 'paint' the walls with
    a slurry of some kind (it came in paint cans but was very thick). It
    worked miracles; presto, humidity stayed where it should. Wish I could
    tell you the name, but probably some paint store could help.  Since I
    hadn't seen any such suggestion, just thought I'd throw it in the hat.
    L.Skjelstad